MS. INDIRA LAKSHMANANThanks for joining us. I'm Indira Lakshmanan sitting in for Diane Rehm. Diane is getting a voice treatment. A seven or eight-year-old girl is likely more interested in soccer or dolls than boys and training bras so how should doctors and parents respond when a child enters puberty at this age? It's a question being raised more often as girls start puberty younger and younger.

MS. INDIRA LAKSHMANANTo discuss the causes of early puberty and how to respond, I'm joined in the studio by Dr. Paul Kaplowitz of The Children's National Health System. And joining me by phone from the studios of KQED in San Francisco, Dr. Louise Greenspan and Dr. Julianna Deardorff. They're the co-authors of the book, "The New Puberty." Thank you all for being here.

DR. PAUL KAPLOWITZWe're glad to be here.

DR. LOUISE GREENSPANThanks for having us.

DR. JULIANNA DEARDORFFThank you.

LAKSHMANANWe're glad your comments and your questions on this sensitive topic throughout the hour. We want to hear from you. Do you have a daughter? Is this something that you have experienced as a teacher or observed? Or are you a doctor who's treating girls like this? Call us on 800-433-8850. Send us your email at drshow@wamu.org or join us on Facebook or Twitter.

LAKSHMANANDr. Kaplowitz, tell us how many girls are going through early puberty today and what age is considered early?

KAPLOWITZWell, that's a difficult question. The traditional definition of precocious puberty is the appearance of any signs of puberty, be it breast or pubic hair before eight years of age. And several studies done in the past couple of decades published in the late 1990s and up until a few years ago show that actually a fair number of girls in the range of 10 to 25 percent actually have some signs of puberty starting before age 8.

KAPLOWITZIn many cases, it's just pubic hair, which is not the same as true puberty, but even breast development seems to be starting earlier and it very much depends also on ethnicity because we tend to see this much more in African-American girls than in Caucasian girls. And Dr. Greenspan can comment because she was co-author on a paper which looked at this very question.

LAKSHMANANWell, Dr. Greenspan, let's talk about that. Can we take a step back for a second and let me ask you, what is puberty and how does it work?

GREENSPANYeah. So when the lay public hears the word girl's puberty, I think a lot of people immediately leap to first period. And when endocrinologists like Dr. Kaplowitz or myself think about puberty, we're thinking about a process that takes place over several years, usually starting with breast development, typically a little bit of breast budding, which may or may not be something parents notice, but is something that doctors can feel for.

GREENSPANSo the little bit of breast budding is one of the first signs and then the other sign is often pubic hair, although, as Dr. Kaplowitz said, isolated pubic hair is not necessarily the same thing as true puberty. But the combination of breast development and pubic hair are usually the first signs of puberty and are then followed several years later by the first period.

LAKSHMANANSo Dr. Deardorff, should we be troubled by this trend or is this just the new normal?

DEARDORFFWell, you know, it's funny because initially people were calling it the new normal and in large part, that's why Louise and I wrote a recent book about this. We were concerned because early puberty leads to negative consequences for girls and that's an issue. You know, some of the things that happen in adolescence that have been linked to early puberty are things like higher rates of depression, anxiety, body image issues and also earlier substance use and sexual initiation.

LAKSHMANANDr. Greenspan, what are, you know, when you hear about that, earlier sex initiation, substance abuse, I mean, that's all very troubling. What are the signs that a parent can look for to stop that before it happens?

GREENSPANI think the first thing is to know that children who are having early pubertal development are at higher risk of those subsequent things happening, but it's not inevitable. So I think it's a matter of being in touch with your daughter, know what's going on in her world and starting to have conversations early on about what's happening with her body because that indicates to her that you're someone she can go to.

GREENSPANAnd then, when she's faced with these other challenges, hopefully, she'll be addressing them with other adults, the parent or other adults in her life that she feels comfortable talking to about these things because you've modeled that by talking about the body. These events are not inevitable. I mean, really want to make sure parents feel empowered to make the changes they need to to protect their daughters.

LAKSHMANANDr. Kaplowitz, when you see a child who's experiencing early puberty by the conditions that you define for us, what is the course of action? Does it need to be treated?

KAPLOWITZActually, a fairly small percentage of the girls referred to us for signs of early puberty require any treatment. In our experience, about 60 percent of the girls that we see have mainly pubic hair and body odor, which is related to hormones coming from the adrenal glands, not from the ovaries and it can be several years after the pubic hair appears that breast development starts.

KAPLOWITZSo those kids do not need any treatment. Now, other kids who -- the girls who start early breast development, it really depends on how rapidly it progresses. I would say, in many cases, a little breast development is there and then six months later, a year later, it hasn't changed very much. So not all puberty is progressive. On the other hand, if you have a girl who, in a six month period, the breasts are clearly getting bigger and they're also having a growth spurt, those are the girls that might be considered for treatment.

KAPLOWITZBut those really represent a minority of the girls that we see. And so my own policy is unless the puberty is fairly advanced at the first visit is I don't do anything until I see them back at least one time so I can pick out those who would really benefit from treatment because, as we'll talk about later, treatment is quite expensive and we don't want to use it if it's not necessary.

LAKSHMANANYeah. So medical intervention usually not necessary. Dr. Deardorff, are there other effects of early puberty, like emotional or psychological consequences?

DEARDORFFWell, sure. And that's -- it's funny 'cause Louise always says that one of the first signs of puberty is slamming doors. And really, you know, I think that the misconception in the public is that hormones cause emotions and actually what we've found is that hormones augment emotions that are kind of already there. So this is where parents become really important. And hearkening back to Dr. Greenspan's point, it's not a bright line from early puberty to problem outcomes for these kids.

DEARDORFFParents really matter. And so when a girl is going through puberty early, but her brain hasn't kind of caught up in a way to regulate some of those emotions, it's really important that parents provide kind of a safe, stable environment to scaffold her through that transition because if you think about hormones augmenting emotions, parents are kind of the buffer to provide the warm, protective, nurturing environment that can help her regulate better when she's feeling out of control.

LAKSHMANANDr. Greenspan, what about boys? Are they starting puberty earlier, too, and what are some of the effects of that perhaps?

GREENSPANThat's a very good question and I think to answer that I have to make a point about one of the causes of the girls' early onset of puberty, which is obesity and overweight. And when we think about fat tissue and the effects that that has on the body, fat tissue may have an opposite effect on boys, specifically fat tissue can increase your estrogen and estrogen-like hormones in the body.

GREENSPANAnd for girls, that may mean an earlier onset of breast development. However, for boys, that may delay puberty so the data on boys is a little less clear. There's some data that boys are starting puberty earlier, but there's also some data that severely overweight boys may actually start puberty later. So we're not quite sure what's going on in boys, but, again, the same -- the things that may cause early puberty in girls may actually cause delayed puberty in boys.

LAKSHMANANBut in terms of overall trends, we're seeing overall trends of girls reaching puberty earlier, boys reaching puberty later?

GREENSPANI'd say with boys, we're not sure and it might be unchanged or there may be some groups that are starting earlier and some that are later, but we do have a big disconnect now between the onset of puberty in girls and the onset of puberty in boys. It was always about a two-year difference and now maybe it's an even longer difference, which makes fifth and sixth grade even more complicated.

LAKSHMANANYeah, as if middle school weren't hard enough already. All right. Dr. Deardorff, you say obesity doesn't explain the entire picture. What are these endocrine disrupting chemicals? What's their role?

DEARDORFFWell, it's interesting. You know, when we refer to endocrine disrupting chemicals, we're talking about hormones -- or I'm sorry, chemicals that mimic hormones in the body and, in particular, we're interested, when we're talking about girls' puberty and breast development, in those chemicals that mimic estrogen in the body.

DEARDORFFWe are not sure. A lot of the data is coming from animal studies that have show that certain chemicals that are very commonplace that are found in plastics, in beauty products that girls and their mothers use, that are in household cleaners, maybe in the things that you sit on, like your sofa, that some of those may act like estrogen in the body of animals and have been shown to lead to earlier puberty.

DEARDORFFNow, this research is in its infancy in humans. And when you think about all the chemicals that we're exposed to daily, we know very little about the synergy of these chemicals as well. So this is right where the research is in -- yeah, go ahead.

LAKSHMANANNo, I was just gonna say, we hear about phthalates and parabins and BPA in pesticides and detergents and, you know, Dr. Greenspan, I'm wondering what is a parent supposed to do about this because every parent knows that plastic is totally ubiquitous in the life of a child from bottles to cups to toys to, you know, notebooks. It's everywhere.

GREENSPANI would say chemicals are ubiquitous and it is impossible for any of us to live a chemical-free life so we have to do the best that we can with the knowledge that have right now. And that knowledge does change. One of the reasons we wrote this book was to really give a resource for parents. And we have a whole chapter in "The New Puberty" that really outlines things that we can do that we know would be safer.

GREENSPANFor example, we think that plastics are dangerous. The animal data is very strongly suggestive that there are compounds in plastics that have negative effects on health. Human data is..

LAKSHMANANHold that thought because we're gonna have to take a short break, but I look forward to hearing from all of you callers and your questions. Stay with us.

LAKSHMANANWelcome back. I'm Indira Lakshmanan, sitting in for Diane Rehm. We're talking about early puberty, its causes and consequences, this hour with three experts on the subject, Dr. Paul Kaplowitz of Children's National Health System, and on the phone from KQED in San Francisco, Dr. Louise Greenspan and Dr. Julianna Deardorff, who are co-authors of the book "The New Puberty." Let's take a call from Ben in Pittsburgh, PA. Ben, go ahead, you're on the line.

BENHi, thanks for having me, Indira, and I hope Diane's voice treatment goes well.

LAKSHMANANAbsolutely.

BENMy question is, basically I have a, I'm expecting a baby girl in August.

LAKSHMANANOr your wife is.

BENYeah, well, right, yeah.

LAKSHMANANBoth of you.

BENAnd I'm kind of interested, you mentioned about the plastics and the estrogen mimicking chemicals, but I'm wondering about if there's ever been any research or what the train of thought is in the scientific community regarding to need bovine growth hormones that are given to cows and other, and other, you know, different cattle and goats and all that and as far as the milk, you know, from a conventional dairy farm that would be using those hormones and if any of those have been linked to some of this early onset puberty.

LAKSHMANANOkay, good question from Ben. How serious is exposure to these chemicals when a mother is pregnant, Dr. Kaplowitz?

KAPLOWITZWell, to the answer the question of bovine growth hormone, that's, certainly if you look on the Internet, there are many references to the possibility that drinking milk from cows treated with it may accelerate puberty, but there really is no scientific basis for this speculation. First of all, bovine growth hormone is not active in humans, it's different, and second, the growth hormone that might have made its way into the milk would be digested in the stomach and the intestines, and so it's not absorbed intact into the bloodstream.

KAPLOWITZSo I think you can rest assured that bovine growth hormone or other animal growth hormones in milk is not a factor in the terms of earlier puberty in girls.

LAKSHMANANInteresting because that's been a real concern and a real cause, I think, of the sort of movement towards organic milk for sure.

KAPLOWITZRight.

LAKSHMANANDr. Greenspan, another reason or risk factor, perhaps, for early puberty is stress, right?

GREENSPANI'm going to let Dr. Deardorff take that question because she's an expert in that field.

DEARDORFFAll right, so the research has shown unequivocally that girls who are growing up in kind of highly conflictual, unpredictable environments with low parental warmth are more likely to enter puberty early. And this has been decades of research. There's also been research on early sexual abuse, and that has also shown to push girls into puberty earlier. And so that's lesser known among the public.

LAKSHMANANNow Dr. Deardorff, you've also done research on income and its link to early puberty. Tell us what you found on that.

DEARDORFFRight, so in the past, girls who, in the distant past girls who had come from families with higher income tended to go through puberty earlier because there was better nutritional quality. You had more access to food. And we know in times of famine that girls will not enter puberty because they don't have enough body fat to enter reproductive readiness, so to speak.

DEARDORFFHowever, now what we're seeing is that it's kind of tipping the other way, and with girls' over-nutrition and higher caloric intake, they tend to go through puberty earlier. So who are those girls? Well, they tend to be girls who are living in areas of poverty, and so what we're seeing now is that girls in low-income areas tend to enter puberty earlier.

LAKSHMANANOkay, let's take a call from Mason in Indianapolis. Mason, you're on the line.

MASONGood morning, thanks for bringing up an interesting subject. One of the questions I had was about population like we're discussing on the question of puberty. One of the panelists had mentioned that obesity was a pretty interesting tactic. So I was wondering if there was any research or international research that compares the U.S. versus other areas that might have precocious puberty going on. Thank you.

LAKSHMANANOkay, Dr. Kaplowitz, can you take that?

KAPLOWITZThere have been many studies published from all parts of the world, and I think the best way to summarize them is to say that the trend is not just seen in the U.S., it's seen in multiple countries, probably more so countries closer to the equator than countries in the northern latitudes. But major factor is likely to be, certainly in the developing countries, a switch from a more traditional diet to a more Western diet, which results in greater, perhaps better nutrition or perhaps over-nutrition, and that's certainly a factor.

KAPLOWITZBut these studies have looked at not so much the age at which breast development starts the age at menarche, and that's definitely dropped in many countries of the world.

LAKSHMANANOkay, menarche, define it for us?

KAPLOWITZMenarche is the age at which you have your first period.

LAKSHMANANOkay, thank you. Let's take another call from Veda in Reston, Virginia. Veda, you're on the line.

VEDAOh hi, thank you so much for taking my call.

LAKSHMANANThanks for calling.

VEDAAnd thanks so much for dwelling on this, on this topic. It's really much needed. My comment has to do with my experience with my now nine-year-old daughter. But she was overseas, we're overseas, for a couple of years, came back when she was seven, and because I work, she was doing school lunches. She was eating lunches at school on a regular basis. And I noticed a difference in her.

VEDANow, she's not overweight. She's actually very active. She has a very high metabolism, is in sports, etcetera, but I think it has a lot more to do with what the kids are eating than we're alluding to, and I believe that corporate America has such a hold on the educational system in this country when it comes to food. And when I volunteer every now and then, once in a blue when I volunteer, I notice that the children in her school that are getting school lunches, you know, that are paid for by the county, I live in Fairfax County, those children can drink as much milk as they want, and they don't have to pay. But if they ask for water, they have to pay for water.

LAKSHMANANOkay.

DEARDORFFOh my goodness.

LAKSHMANANThat is really interesting. That's surprising. So we have here a woman who, when her daughter started eating school lunches in the cafeteria, she started developing more. Dr. Greenspan, you know, there's a real concern here about nutrition and its link to early puberty. Tell us about Veda's questions, and are there other things at play, as well, other kinds of hormones in the food?

GREENSPANSo specifically related to school lunches, I agree with our caller that there are some major problems, and I think a lot of people are trying to change school lunches. Historically, school lunches have not been made of the most quality nutrients because they're trying to prevent spoilage. So there's been a lot of preservatives and a lot of processed food.

GREENSPANAnd we do think that the more highly processed foods have more negative effects on your metabolism. So some of the compounds that are added to food, for example, may make your body metabolize carbohydrates differently and raise your insulin levels, which itself can predispose you to type 2 diabetes and obesity. It's a very complex subject, but we do think that there's probably something in the food supply, whether it's just the pure calories and extra calories.

GREENSPANFor example, drinking excessive milk is just too many calories, versus the fact that highly processed foods are bad. Both of those can cause overweight, and as I said before, fat tissue itself makes estrogen.

LAKSHMANANWhat...

GREENSPANGo ahead.

LAKSHMANANI was just going to ask what about hormones in meat and soy.

GREENSPANSo this is a question we hear about a lot. I'm going to separate that out. The hormones in the meat, so to speak, I will go back to Dr. Kaplowitz' answer. I completely agree with him that the growth hormone in the meat is really a negligible. What's more concerning about meat and chicken, in my opinion, is the antibiotics. So antibiotics in livestock are concerning because we're worried that they may be contributing to the obesity epidemic.

GREENSPANWe know that there's lots of evidence that antibiotic use in children, medically necessary use, is associated with higher rates of obesity. So the concern is that chronic, low-grade exposure to antibiotics in the meat and chicken may also be contributing. And that processed food that's in school lunches is more likely to have been treated with antibiotics. So that is one concern.

GREENSPANThe second question you asked about is soy, and that's another one that if you look on the Internet, you're going to find that it tells you that soy causes early puberty. And our data and the work of others actually suggests that that is incorrect. Julie and I were part of a study here in the Kaiser system, Kaiser Permanente, in the Bay Area, and the study suggested that the girls who ate a higher amount of soy went through puberty later.

GREENSPANAnd there's other data that suggests that soy intake in childhood is protective against breast cancer. So we think that soy is probably being vilified and that it's a lot safer than the lay public thinks that it is.

LAKSHMANANSo back to the tofu.

DEARDORFFAnd that's not soy additives.

GREENSPANYeah, we're talking about, thank you, Julie always reminds me to say this, we're talking about the balance of the proteins, the isoflavins, which may be estrogen-related, in whole tofu, whole soy foods like tofu or tempeh or soy milk. We are not talking about highly processed soy foods because when you get into something like soy protein isolate, the balance of the proteins is extremely different, and there are animal studies that suggest that that actually may contribute.

GREENSPANSo we really emphasize eating, again, unprocessed foods, whether it's soy or meat, really eating foods that's closer to the natural way that it was grown or made.

LAKSHMANANOkay, so tofu is okay, and soy milk is okay, thank goodness. All right, let's take a call from Jean in Grand Rapids, Michigan. Jean, you're on the line, go ahead. Jean? Okay, maybe we lost her. All right, Dr. Greenspan, I want to ask you, go back to one point. How can a parent or a teacher talk to their daughter about what's happening to their body? Because that seems like a really sort of delicate issue.

GREENSPANIt is, and I think one thing we really emphasize is not having one talk. We actually have a chapter in our book entitled "Start the Conversation, Don't Have the Talk." It's really important that right from the beginning, as early as possible, adults talk to girls about these things in a way that makes girls realize it's okay and that the adults in their lives are comfortable.

GREENSPANSo one place that I think is easy to start is with body odor because body odor actually, as Dr. Kaplowitz pointed out, starts a lot earlier than real puberty, and it's not real puberty, but it can be a precursor. And body odor is not that threatening to most people. Armpit odor is something that a male or a female can talk to a boy or a girl about, and they can demonstrate how to wash under their arms and how to clean their armpits without having to use deodorant, and it's really not threatening. You can still be mostly clothed to talk about this or even demonstrate it.

GREENSPANAnd I like to start with that because I think it's a really easy, non-threatening place to start. It's really important that adults feel comfortable. So if you're really embarrassed by this, then it may be better to have an adult who's slightly less embarrassed talk to your children about it.

LAKSHMANANI'm Indira Lakshmanan, and you're listening to The Diane Rehm Show. I mean, there's also this challenge about staying emotionally close to a daughter who's going through these changes without helicoptering. Dr. Deardorff, how do you deal with that? I think both of you are actually parents of girls.

GREENSPANYes we are.

DEARDORFFYeah, we are. And I pack my daughter's lunches for school. At any rate, I, you know, staying emotionally close is hard in our digital age. People are on their phones and their iPads, and as girls get older, they, too, are playing games when everyone's at dinner. And I think that can create a lot of emotional distance. And so I think the first thing we have to do is put down our electronics and actually have conversations with our children.

DEARDORFFAnd as Louise suggested, when it comes to puberty, use the right terms, normalize what they're going through, but then also make sure you're having fun with your kid, and you're finding ways to connect, because if you check out for a couple years, and she turns 13, it's much harder to try to get that relationship back.

DEARDORFFAnd so when a girl is young, and they want your attention, I think it's a really nice time to lay a foundation and a groundwork for, you know, what we refer to as emotional closeness or bonding with your kid. Now for dads, it gets tricky, and I have a lot of conversations with dads or moms who are concerned because as a daughter goes through puberty, they tell me that their husband is tending to withdraw more, or dad says he feels less comfortable hugging his child, you know, as she's growing bigger and growing breasts.

DEARDORFFAnd I think that's a really important place to recognize your feelings and not signal to her that you feel awkward with her because of the way her body is changing. And so, you know, keep hugging her but also start doing things that are fun for you and your daughter so that you can build, develop and strengthen that emotional relationship.

LAKSHMANANShould sex be part of the conversation, either for mothers or fathers talking to girls who are hitting early puberty?

DEARDORFFWell, you know, sure, sex should be part of the conversation eventually, and that's why it's a conversation and not a talk. You're not going to go from, as Louise says, stinky armpits all the way to sex in the same conversation. It's really important to pay attention to where your child is developmentally, and so for instance if a girl's going through puberty earlier, the first signs are going to be barely visible, if at all, to the outside world.

DEARDORFFSo when we're talking about seven- and eight-year olds, her body is changing, but others might not notice, and so I think it's really important for parents and other adults in the girl's life not to sexualize what is normal pubertal development early, and to start having conversations about sex when it's developmentally age appropriate, when you and she are ready, and that can vary from family to family, when that conversation happens.

LAKSHMANANAnd along those same lines, how important is peer support for a girl who's going through early puberty? And I think sometimes her friends are going to be bringing up issues that maybe her parents aren't, maybe not in the most constructive way. Dr. Greenspan, can you take that?

GREENSPANYes, that is a very, very important factor, and it's really important that the parents know who the friends are, and we talk about this for many reasons. You can do a little damage control. But that's where being the adult in your child's life who your child's comfortable talking to is really important because the kid might come home and say, hey, Olivia said this at school, is that true, as opposed to keeping in whatever her friend said inside and worrying about it.

LAKSHMANANSo making sure that your door is always open for your child to talk to you.

GREENSPANCorrect.

DEARDORFFLouise and I really advocate for starting puberty education, and I'm sure Paul would agree, puberty education earlier in the schools. So for instance, in my daughter's school, it got delayed to sixth grade, and by that time, when you're thinking about when girls are entering puberty, most of them have already started the process and are already dealing with some of the changes. So we are really, really advocating that schools start in, at the latest, second semester of fourth grade, given this kind of movement towards puberty starting early.

DEARDORFFAnd that influences the peer group because everyone's on the same page, with the correct terminology. There's not a lot of myths flying around.

LAKSHMANANWe have just a short time before our break, but since you're both moms of young girls, can you give us some tips, a quick tip on what one of you did to talk to your girls that was helpful?

DEARDORFFNumber one, I would say please use the correct terms, you know. So call things what they are and get them started early with using those terms. Don't use your visitor is coming or Aunt Flo, please.

GREENSPANSay the word period.

DEARDORFFSo ban euphemisms.

GREENSPANPlease.

LAKSHMANANIs that right, Dr. Greenspan?

GREENSPANI agree. I think we don't need to use the word menarche, but I do think using the word period rather than Aunt Flo is a good idea. I think what I've done with my children is really made them understand that this is something we all go through. A lot of kids think that these changes are so odd, and why are they happening, especially if they're the first ones. They don't see it in their peers, and they don't know what's happening.

GREENSPANSo if girls and boys know that mom gets her period every month and that daddy has to wear deodorant, then they know that these are very normal things.

LAKSHMANANThat's right. I mean, that's partly also them seeing you do your daily ablutions and it not being a big secret with the door closed to the bathroom. All right, we're going to take a short break now, and when we're back, we'll have more of your calls and your questions. Please stay with us.

LAKSHMANANWelcome back. I'm Indira Lakshmanan, sitting in for Diane Rehm. We are talking about early puberty in girls, the causes and the consequences, with Dr. Paul Kaplowitz or the Children's National Medical System, Dr. Louise Greenspan and Dr. Julianna Deardorff, who are co-authors of the book, "The New Puberty." We've gotten a number of messages from Twitter and Facebook and email from people who really want that conversation about what parents can do about plastics.

LAKSHMANANAnd the relationship between plastics and early puberty. People are really interested in this topic. Can we go back to that and clarify that? Who would like to take that?

GREENSPANThis is Dr. Greenspan.

LAKSHMANANAll right.

GREENSPANI can take that. Plastics is very complicated. One of the big compounds that we have been worried about in plastics is something called bisphenol A, or BPA, which most people now are familiar with. Bisphenol A was initially introduced as a synthetic estrogen, as in one that might have ended up in the birth control pill. It wasn’t so great at that, and then somebody realized it was going to be a good platicizer, so it was used at a lower concentration in plastics. The concern is that it may leech out into foods under certain circumstances.

GREENSPANParticularly when food is heated and under other conditions. So, what I mentioned before was that there's a lot of animal data that shows that BPA is dangerous, but we can't really do the studies in humans, where we have one group of girls grow up exposed to BPA and one group of girls that isn't. And this highlights some of the challenges we face when studying endocrine disrupting chemicals. But we do have enough animal data to suggest that there are harmful effects from BPA.

GREENSPANSo, we recommend taking a more cautious approach and trying to avoid it without increasing your risk of being exposed to other things. So one example is that we recommend not microwaving in plastic. We know that glass is safe. There are many glass containers you can buy, inexpensively, and we recommend using a glass containers when you microwave. We also recommend if you can avoid storing food in plastic, that's a good idea. There are many, many BPA free plastics now on the market, but some of them have BPS and other compounds that may also be concerning.

GREENSPANSo, if you can use stainless steel water bottles, that's another place, as an example. You can't eliminate all plastics from your life, but the more we get away from using those containers and those things, I think is probably better.

LAKSHMANANI suppose metal is an alternative for parents who are worried about their toddlers breaking glass on the floor.

GREENSPANYeah, there's lots of metal containers. Those tend to be a lot more expensive. The metal food containers are harder to obtain, but they are obviously very safe.

LAKSHMANANDr. Deardorff, did you want to add something to that?

DEARDORFFWell, I was thinking, you know, we talk a lot about plastics, but I think people spend a little less time thinking about beauty products, lotions, fragrances, things we slather on our skin and on our hair every day. And we use a number of different products ourselves and on our children. And so, becoming a savvy consumer is probably one of the best things that parents can do right now, even in a precautionary way. Even if we're not sure what some of the effects of some of these things are, so we do provide a list in our book of things that should try to avoid if you can.

DEARDORFFAnd one resource that both Louise and I use and we recommend to our patients and people in our lives is an app called Skin Deep, by the Environmental Working Group. Where they actually score different products based on what they think the chemicals are in them and what the science is behind those chemicals. And so, that's an app available on your phone, it's something you can go online. You can scan barcodes while you're in the store to see what the rating is and those kinds of things.

DEARDORFFThose are some of the preventative measures that parents can take. Now, are those going to stop a girl from going into early puberty? We just don't know. I mean, like I said, this research is really in its infancy, and some of these chemicals may disrupt puberty in a different way. It may actually cause delayed puberty. Doesn't mean that that's good. We're trying to figure out the balance of what's going on here.

LAKSHMANANAnd so, you do have, in your book, "The New Puberty," a list of chemicals that people can look for in lotions and perfumes and things they may use on their children, to avoid.

DEARDORFFYes, and we also talk about where some of those are found and what some of the preventative measures are that you can use in your home.

LAKSHMANANOkay, good. We have an email from Andrew, who says my four-year-old daughter was recently diagnosed with precocious puberty, due to breast budding, showing in her four-year-old checkup. And pubic hair was also starting to be noticed. After numerous visits, tests, and painful delays, the cause was determined to likely be a Rathke's Cleft Cyst pushing on her pituitary. So, this writer says it's important in this discussion not to overemphasize environmental issues that may only be potential causes. Dr. Kaplowitz, can you talk about that?

KAPLOWITZWell, four, age four is an unusual age for puberty to present. We see a lot of children who develop breasts between ages zero and two who have a little bit of breast development, which does not progress and is basically considered a normal variation. And we call that premature thelarche for early breast development. And puberty starting in seven-year-olds is often true precocious puberty, but in a four-year-old, it's a little unusual at that age. And so, that's probably why the physician did an MRI.

KAPLOWITZAnd I can't be sure that the Rathke's Cleft Cyst, unless it's quite large, is the cause of it, but I think that if the hormone levels are clearly elevated and the puberty is clearly progressing, then this child ought to be treated, but I think it's an unusual case.

LAKSHMANANWe have a message from Meredith in Alexandria, Virginia, who wants to know about the long term reproductive effects of early puberty. And she says that she feels this coincides with another contemporary women's health issue, which is the delay in starting families. So, if women are having babies later in life, in their 30s instead of their 20's, or even in their 40s, and starting puberty earlier, is this going to contribute more to infertility, birth defects, other reproductive problems.

LAKSHMANANIt relates to another listener to wrote in and asked whether early puberty is linked to early menopause. Dr. Dearborn, can you take that? Deardorff, I'm sorry.

DEARDORFFYou know, I'll answer what I know about that area, and then maybe Paul can fill in a little bit. From the research that I have read, it doesn't appear that early puberty is linked to lower fertility or other kinds of reproductive issues. Now, reproductive cancers yes, but not in terms of fecundity, so to speak, or fertility. There is -- there have been some work done on the links between early puberty and early or later menopause. I don't think any of those have borne out any high correlation.

DEARDORFFNor have I seen things that talk about offspring having birth defects or any other kinds of issues like that. So, Paul, I don't know if you have any other...

KAPLOWITZYeah, I think you summed it up, our knowledge, quite well, on that topic.

LAKSHMANANAll right. Good. So that's settled. Are there any evolutionary arguments for why girls are experiencing puberty earlier? Dr. Kaplowitz.

KAPLOWITZYes. This is something that we've been talking about for a while. That one of the mechanisms by which obesity may be related to earlier puberty in females is through a hormone called leptin. Leptin is produced in fat cells and it's a very important regulation -- regulator of appetite and body composition, but there's also evidence that leptin is required for, not just humans, but for lower mammals, as well, to progress through puberty. So, one theory is that young obese children, because of higher leptin levels, are more likely to progress through puberty at an earlier age.

KAPLOWITZAnd the evolutionary advantage of this is that in times of food scarcity, which all, which early humans and all mammals go through from time to time, fat stores are low and you don't want to put your energy into reproducing when you don't have enough fat stores to support a pregnancy.

LAKSHMANANOkay. Let's take a call from Amy in Jacksonville, Florida. Amy, you're on the air.

AMYThank you for taking my call. I actually have two questions. My daughter was born, she was 10 pounds, 24 inches. And at seven...

LAKSHMANANThat was a tough delivery.

AMYYes, it was. And at seven, she developed precocious puberty. And, I mean, within four months, she developed, she had pubic hair, she had breasts. So, she was treated with Lupron until she was 10. So, my question is does her weight impact precocious puberty and also, is there long term effects for her taking Lupron for the three years that she took it?

LAKSHMANANInteresting question. Thank you, Amy. Would someone like to take that in San Francisco? Dr. Greenspan?

GREENSPANYes, I can start with the birth weight. Birth weight's complex. Low birth weight has been associated with earlier onset of pubic hair development. High birth weight may be reflective of maybe potentially diabetes in pregnancy or overweight, and there's some data that suggests that might be contributing. But that research is ongoing. Our group is looking at that as well as other groups. In terms of the Lupron, I'll answer that, and then I think Dr. Kaplowitz can answer it too.

GREENSPANLupron is used for a number of reasons. In girls like this, it's specifically used because the rapid progression of the puberty is psychologically too hard for young children to handle. For very young children, such as the four-year-old, Lupron can also promote acquisition of normal height. It doesn't make that much of a difference when you start it when you're eight or so, but certainly, when you're four, if you rapidly go through puberty, you will be very, very short. And Lupron can prevent that from happening.

LAKSHMANANDr. Kaplowitz.

GREENSPANIn the long term, there is not a lot of data looking at Lupron being dangerous, so we think it's perfectly safe and that it's safer than the alternative of allowing girls to go through puberty early. But I'm curious about what Dr. Kaplowitz has to say about that.

KAPLOWITZYeah, I think there has been enough published data to suggest that Lupron is safe. There were concerns that it might promote further obesity, but I think the data shows that it doesn't. That once you stop Lupron, periods usually will start within six to eighteen months, and as we mentioned earlier, reproduction is not a factor. So, it's a safe drug if used appropriately. One of my things that I've found is that, as Dr. Greenspan mentioned, the medical use of these drugs, like Lupron, is to prevent early epiphyseal fusion, fusion of the growth plates, and prevent short stature.

KAPLOWITZBut when I talk to parents of seven or eight year old, early maturing girls, their major concern is they don't want their children to have periods early. Cause they don't think children can handle it, and I always advise them that it takes at least two, and often three or more years from early breast development to onset of period. So if you have an eight-year-old child with a little bit of breast development, the earliest they're going to start their periods is age 10 or 11.

KAPLOWITZAnd most girls can handle that. It's the girls who are starting periods at age nine or less that are the ones that struggle with that.

DEARDORFFAnd that's actually great news for parents, cause they have forewarning, and they can start the conversation.

LAKSHMANANI'm Indira Lakshmanan and you're listening to "The Diane Rehm Show." All right, let's take another call from Sarah in Indianapolis. Sarah, you're on the air.

SARAHGood morning. So, I'm hearing that puberty is moving earlier as an overall trend, but I'm also hearing, I believe Dr. Kaplowitz said, that most of the girls who are brought to him do not require treatment. And it makes me think back, I didn't hit puberty particularly early, but I jumped straight into a C cup. And my mother refused to buy me a bra because you're too young, you're too young, you're too young. And I still remember, I'm 30, I still remember how painful that was for me, both physically and emotionally, because I was being mocked at school. And my mother was telling me I was strange.

SARAHAnd so, we've been talking about this on an overall scale, but I think the thing that hasn't been mentioned is how important it is for parents, even if they think there might be something wrong, to not jump to that conclusion with their children. And not tell their children that whatever is happening to them, that they're different. Their kids just need support.

LAKSHMANANWhat a good call. Thank you so much for calling in, Sarah. I mean, let's address that question, because that is very painful. It's difficult enough to go through that period, but for parents then, to make it harder for the children, for making them feel different.

DEARDORFFIt's a great point, and I'm so glad that the caller called in. What we really recommend is to normalize this process for girls, no matter how quickly -- it sounds like the caller really had rapidly progressing puberty. No matter how quickly it happens, no matter how quickly it starts, whether it's early or late, sometimes girls who are late are also very self-conscious. And it can really get wrapped up in your body image and how you feel about yourself. And so, as parents, what we can do is really normalize these changes. There's lots of individual variability.

DEARDORFFAnd let girls know that this is their process and this is their pace. One great thing that we have now that we didn't have in recent years was a lot of products that actually are made for young girls. So, whether it's sanitary products that actually fit them appropriately, or bras that are available that actually work for them, we're fortunate in that regard. There's lots of choices. There's lots of options. And it's really not as stigmatized the way it used to be.

LAKSHMANANLet's take another call from Lisa in Fairfax, Virginia. Lisa, you're on the air.

LISAHi. Thank you for taking my call.

LAKSHMANANSure.

LISAI have a son and daughter. They are 10 and 11. So, one question I wanted to ask is when my husband and I are taking showers, what is appropriate to allow the kids to enter the bathroom and see us? You know, should we say, this is something private, or hey, come on in. You know, this is what will happen at the end of puberty. You know, this is kind of an uncomfortable situation, you know, having a son and a daughter, so I would love it if you could address this and I'll take your call offline.

LAKSHMANANOkay, great question. Who can take that for us, because it is something that parents think about as their children get older, same sex or opposite sex. What do you do about the bathroom time? Go ahead, Dr. Deardorff.

DEARDORFFYeah, I think we can all answer it in different ways. I mean, there is so much individual variability between families and their comfort levels. I mean, it varies based on culture, it varies based on context. So, I really think it has to come down to what's comfortable for you and for your family. I know that's a tough answer, but it really does come down to what's comfortable for you. Now, where I kind of draw the line is when it comes to talking to your kid about puberty.

DEARDORFFSometimes, we're not comfortable, and we have to jump in and be brave. But in terms of disclosing some of those, you know, you're taking a shower and how do you feel about your body, you know, that's a very personal decision.

LAKSHMANANWe've got just a short time left. Dr. Greenspan, any last thought on that?

GREENSPANI agree with Julia. I think it's hard. And you may feel more comfortable being naked in front of your same gender child and that's okay, too. But we do want to make sure that boys know what's happening with the girls and women as well as girls knowing what's happening with the boys and men. Because we need to be making sure that the boys are not contributing to body shaming, for example, of the fourth grade girls who have chest development. That sort of thing.

LAKSHMANANThat's a really good point. 30 seconds left, Dr. Kaplowitz. Let's get the male perspective on that, as a dad.

KAPLOWITZWell, I agree with Dr. Deardorff. It's a very personal issue and yes, I was more -- I only have two sons. So, I don't have the experience of growing up with daughters. But yeah, I think you have to become comfortable with whatever path you decide to take.

LAKSHMANANWhat a fascinating hour. Thank you so much to all three of you and to all of the wonderful callers. I'm Indira Lakshmanan, sitting in for Diane Rehm. Thank you so much for listening.