MS. KATTY KAYThanks for joining us I'm Katty Kay of BBC World News America sitting in for Diane Rehm. When Annie Murphy Paul was pregnant with her second child she set out to learn as much as possible about how her behavior might affect her fetus. She spoke with numerous experts in the growing field known as fetal origins. In her new book titled, "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives" she shares those discoveries. Author Annie Murphy Paul and Johns Hopkins researcher Janet DiPietro join me now in the studio. Ladies thank you so much for coming in.

MS. ANNIE MURPHY PAULGood morning.

MS. JANET DIPIETROThanks for having us.

KAYThe phone number here is 1-800-433-8850. You can also send us an e-mail with your questions or comments to drshow@wamu.org and you can find us on Facebook and Twitter as well. Annie let me start with you. What is the field of fetal origins?

PAULWell, fetal origins is an emerging science. It's something that has been growing and developing over the past, I'd say 10, 15, 20 years and it investigates the possibility that experiences and events that we encounter in the womb and during the nine months of gestation can affect our health and well-being into infancy and childhood and even into adulthood and old age. And I was coming across these findings as a science writer.

PAULI write for -- about science for magazines and newspapers. I was encountering these findings and finding them quite interesting, quite intriguing on a sort of intellectual level and then I got pregnant and all of a sudden what had been sort of an intellectual exercise suddenly seemed more urgent. I really wanted to know how what I ate and drank and felt and did affected this, this child I was going to have.

PAULSo I decided to, as a pregnant woman and as a science writer investigate this field by looking at a different prenatal influence each month of my pregnancy.

KAYJanet I think a lot of people would think yeah well we know that if we drink too much or we smoke or we take bad drugs then we're going to harm our baby. But this seems to be about more than that.

DIPIETROSo we know some of the major negative influences on the fetus and most of those have to do with doing things in excess, drinking in excess, smoking in excess and so on. And what we don't really know very much about are the lower limits of what's safe and how to raise a healthy fetus.

KAYWhat do we know about the genes of the unborn child Annie and how much they can actually change during those nine months of gestation?

PAULUm hmm, well this is one of the reasons why the period of gestation has become this very exciting sort of cutting edge area of research. We used to believe that you got your allotment of DNA at conception and that was it, your genes were a kind of blueprint that unfolded without interruption throughout your life. And now we know because of an exciting new area of research known as epigenetics that although DNA doesn't change the way that genes are expressed, the way they behave, that can be altered by influences from the environment and that that process of epigenetic modification goes on especially -- with especially great consequences during the time when we are in utero.

KAYSo what you're saying is that the sperm and the egg could come together on day one of the pregnancy and the fetus is conceived with a certain DNA but that what is there at the end of the nine months is not the same. You're saying it's the same DNA but not the same gene performance?

PAULWell epi means 'on' and on top of the DNA code that we inherit at conception there's another code that controls how those genes are expressed, you know how, if you could think of it like a radio control board like we have in this office those genes aren't just off or on they can be tuned up or tuned down and in accordance with environmental inputs.

KAYGive me an example of how this might happen in a fetus, something that might change in terms of the genes?

PAULWell one of the original animal experiments that led scientists to be aware that this could happen involved a strain of mice known as agouti mice and these agouti mice have a gene that in most cases leads them to be sort of fat and have a golden colored coat, a yellow coat and to have certain health problems.

PAULBut scientists at Duke University fed one group of pregnant agouti mice folic acid, folates so that, which is, can help change how genes are expressed in this epigenetic modification process and even though mother and child, you know the mother mouse and the mouse pup had shared the same genes the offspring who had received the folates prenatally were slender, they were brown, had brown coats and they were not predisposed to those same health problems. And the thinking is that it's not the genes that changed it's the way that the genes express themselves leading to an entirely different looking and acting animal.

KAYJanet tell me about the new research that has come out on a group of mothers who were actually in the Second World War who were part of, who had been blockaded by the Nazis. I think actually Annie, you have, you write about this in the book and that this, the effect that that blockade had on their pregnancies and on the fetuses.

PAULRight, well this is...

KAYWhat happened there and what do we know about the state of those children that were then born afterwards.

PAULYeah well, so this is an example of what scientists call an experiment of nature or a natural experiment because especially with pregnant women you could never divide them into two groups and assign each one randomly to a different condition and see what happens. So fetal researchers have often had to rely on natural experiments you know sort of dramatic events like earthquakes and natural disasters and in this case the Nazi siege of Holland during World War II in which many thousands of people in Holland were reduced to near starvation. They were severely malnourished and that included thousands of women who were pregnant at the time and because the Dutch take very good records they were able to follow the fates of the offspring.

PAULMany were born at relatively normal weights and seemed to be fine but in middle age they had higher rates, the offspring had higher rates of obesity, diabetes, heart disease and it's thought that's because of their experiences in the womb.

KAYSo they were born at perfectly normal weight?

PAULIn many cases they were.

KAYBut the problems manifested themselves later in life?

PAULAnd this is what is so mind-bending about fetal origins or the developmental origins of health and diseases as many people call it. It's had a long road to acceptance I think in part because it's so hard to get your head around the idea that something that happened to you as a fetus could have an effect on your life and your health many decades later. But that's what scientists are concluding.

KAYJanet DiPietro, do we know why this might happen? What's the science behind this? Why would someone whose mother was malnourished as those Dutch women were might later on in life suffer from a higher risk of heart disease or obesity?

DIPIETROWell the thinking is, is that the early exposures or deprivations set the early development of the cells and the organs that later are involved in cardiovascular disease or diabetes and so on. And the earlier an influence is present the more persistence its effects on later life.

DIPIETROSo the earliest part of pregnancy in general is much more subject to long-tern influences than later in pregnancy.

KAYAnd how are they getting these cues or signals if you can say that? How do they know what's going on around them?

DIPIETROAt the cellular level...?

KAYYeah.

DIPIETROWell the development in early gestation is a function of the full metabolic processes and those get set according to the fetal origins hypotheses in a manner that then have a sort of cascade over the rest of the child's life. Now the target organ and I actually studied the brain and we looked at the manifestations of the brain in terms of child development, a normal child development.

DIPIETROSo these large studies like the Dutch hunger winter studies are focused on diseases that have to do with various organ systems in the body and our research is focused more on the development of the child under sort of normal conditions of everyday life.

KAYBut fetuses are taking cues as it were from the outside world while they're in the womb. That you are finding?

DIPIETROThey absolutely do so the fetus takes its cues from largely the mother and although the blood of the fetus and the mother don't really mix the placenta is the mediating organ that receives the cues from the mother in terms of things that enter her bloodstream. We used to think of the placenta as sort of a barrier that kept bad things out and in fact it's the opposite. The placenta is sort of a two-way street between the mother and the fetus.

KAYDoes this suggest then that the fetus is more vulnerable than we used to think it was?

DIPIETROThat's a two-edged question because the fetus is essentially a parasite on the mother and the fetus will take from the mom what it can get even to the mother's detriment when it needs it. So we in fact in many ways although the science of fetal origins is extremely exciting as Annie's book conveys the implications for women of what they should and shouldn't do are in many ways over-interpreted by the public. That is, the fetus is much more resilient and less vulnerable than we often think.

KAYOkay and we will talk about that in just a minute after this short break. I'm joined by Annie Murphy Paul. Her book is "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives." Also with me in the studio is Janet DiPietro, she's the associate dean for research and a professor in the Department of Population, Family & Reproductive Health at Johns Hopkins School of Public Health. I'm Katty Kay and we're going to take a quick break, stay with us.

KAYWelcome back. I'm Katty Kay of the BBC sitting in for Diane Rehm. I'm joined in the studio by Annie Murphy Paul. Her book is "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives." Also joining me is Janet DiPietro. She's a researcher with Johns Hopkins School of Public Health. We're talking about the effects -- different effects that can be had on the fetus and what it means for long term health. I have an e-mail here from Tim in Baltimore who writes, "Given that the best outcome for the child is directly linked to maternal health, can your guests comment on the outlook for maternal health during times in which the poor are rapidly getting poorer, and the likelihood that nutrition and other contributors to maternal health might suffer?"

KAYSo, Annie, we talked about that great starvation process earlier and that was, like you said, an experiment that you could never replicate obviously in the real world. But if that was a mass event for individuals if we are going through a stage where women are getting less food and the fetus is therefore perhaps getting less food too, is that likely to have the same effects that they found on that -- on the great winter study?

PAULWell, perhaps not the same effects but I think it's important to realize that these effects that we're talking about are not only found in these extreme situations. The extreme situations are the ones that make it -- provide the circumstances for investigation. But the influences that we're talking about have an impact all across the board. And I think what fetal origins research is showing is that we do indeed need to pay more attention to maternal health as a society if we want our students and workers and citizens of the future to be as strong and healthy and capable as they can be. We're learning that that starts, not with a Head Start program, you know, that we can give to preschoolers or even with a healthy baby program. It needs to start before birth and even before conception in making sure that young women are well nourished and healthy before they even have a child.

KAYI think a lot of people listening to this program might think, oh my goodness, another thing to get anxious about. Another thing that I have to worry about. And particularly pregnant women who are prone to worrying anyway about the state of their fetuses and the health of their fetuses and the unborn child. And they're going to listen this and think, oh, everything I do is going to have an impact on my child.

PAULI was conscious of that every moment that I was working on this book. And, in fact, this was my second pregnancy. In my first pregnancy I was really a basket case in terms of having just those feelings. Feeling buffeted from every side by messages that I shouldn't do this, I shouldn't do that. Any one false step and my fetus would be irreparably harmed. So it was very much part of the project this time to see if there was another attitude available, if there was another way of thinking about pregnancy that was available to us.

PAULAnd I found it in my discussions with scientists who were not by and large full of dire warnings. They were full of excitement and optimism about the possibilities offered by fetal origins research. And by their understanding of pregnancy, which is quite different from the one that you might get from "What to Expect When You're Expecting." They saw pregnancy as a vital dynamic time, a kind of staging ground for the rest of life, in which the fetus is being molded and shaped largely in positive ways for the precise environment that it's going to enter. So that -- from the side of the woman I think that can turn pregnancy into something of an adventure, where you know that you are already having an impact on your child before he or she is even born.

KAYWell, Janet talking of over worrying or just worrying, you've done research on anxiety and stress among pregnant women. What did you find?

DIPIETROSo our finding is essentially that pregnant women should take a big collective breath and stop worrying about the degree to which they're worrying.

KAYI wish somebody had told me that during any one of my pregnancies.

DIPIETROAnd I bet they all turned out fine.

KAYAll fine...

DIPIETRORight, the children.

KAY...all four of them.

DIPIETROSo what our findings have shown is that maternal anxiety and stress during pregnancy of the average woman who's facing the daily stresses of her everyday life -- life today is very stressful, particularly for working women with children -- and the greater stress and anxiety during pregnancy, we found now in two studies including on the neural level, the better the child development is at age two. So this is the opposite of what most people believe, that stress is bad, anxiety is bad, it's going to hurt my fetus. We have evidence from measuring children and measuring things as basic as the speed of the conduction in their nervous system, that average levels of stress and anxiety in fact are facilitative, they advance development.

DIPIETRONow, I say that and I don't mean to imply that pregnant women need to go out and find more things (laugh) to worry about or to be stressed.

KAYRight. This is a complicated message.

DIPIETROVery complicated. We all have plenty of stress. So the message I'd like pregnant women to hear is they need to stop worrying about it. If they're exposed to something or they have their daily lives of stress and hassle and worry, that is not hurting their fetus. It may be changing them in some way, because that's sort of the message from Annie's book.

KAYOkay. But so somebody who's super laid back, living on the lovely farm (laugh) , the weather is perfect, no hassles in their life, are you suggesting then the flipside of this, that might not should be so good for the fetus?

DIPIETRONo.

DIPIETROSee, I'm absolutely not. I'm saying if just...

PAULHere I'm acting as a classic pregnant woman...

DIPIETROThat's right.

KAY... advocate and finding the way to be stressed

DIPIETROI'm not saying women should move off the farm or anything like that. That, in fact, everyone has these sorts of life events that are worrisome to them. So...

KAYAnnie, you write in the book -- and then again, this is the kind of flipside of some of the negative influences, and we talked earlier particularly about malnutrition. We'll get onto the kind of holy grails of pregnancy of, you know, alcohol and that sneaked-in glass of wine in just a minute. But let's talk about some of the positive influences, 'cause you write in your book that a woman -- a pregnant woman who exercises might actually be making their fetus, unborn child healthier and smarter. Explain that. How does that work?

PAULWell, this research is still pretty preliminary, but there was a time when pregnant women were advised not to exert themselves even to -- you know, in the Victorian era they were supposed to be confined to their homes and not move very much at all. And I think we're realizing now that exercise -- moderate exercise during pregnancy is healthy, not just for the woman and for her ability to lose her pregnancy weight once she's given birth, but also there are changes in the heart rate of the fetus during exercise by a pregnant woman that indicate that it's getting the same cardiovascular workout and the same cardiovascular benefits as the woman does when she exercises.

KAYOkay. I think it's time. We talked about that glass of wine. Every pregnant woman worries that they had a glass of wine too much when they didn't know they were pregnant, or can they have a glass of wine? And it's become almost a fetish for pregnant women here that you cannot touch a drop of alcohol. I have a friend who went into a restaurant pregnant in New York and the waitress refused to serve her. Are we going to extremes here or is this sound advice for pregnant women? What's the science?

PAULWell, I'll say -- I'll tell you my personal experience with alcohol during pregnancy. I love my nightly glass of wine. It was extremely difficult to give up during pregnancy. But after reading the research and talking to a bunch of experts I decided that for nine months I would forgo alcohol. And I'll tell you why. It's one reason that this subject is so confusing to so many pregnant women, is that it really is an unsettled area of research. I mean, you'll hear public health experts and maybe even your own doctor use this same line over and over again. There's no safe level -- no known safe level of alcohol that we can expose a fetus to. And that's literally the truth. We don't know what the lower level is, as Janet was saying earlier. We don’t know exactly where a minor level of alcohol consumption shades into a problematic level of alcohol consumption. And we do know that heavy drinking is extremely damaging to the fetus.

PAULAnd it gets even more complicated when you think about things like there may be genetic differences among fetuses just like there are genetic differences among people. Some people can knock back a couple bottles of wine and be fine and other people have a glass and they're on the floor. So fetuses are kind of the same and they have different vulnerabilities to alcohol. And then finally there are other environmental influences separate from alcohol consumption that may affect its effect on the fetus. I cite a study in my book "Origins" about a study of women who were alcoholics during pregnancy. A high number of the poor women who were alcoholics during pregnancy had children with fetal alcohol syndrome. And it was a much lower percentage among women -- affluent women who were also alcoholics during pregnancy. And the thought is that the affluent pregnant women had a much better diet, perhaps less stress in their lives. And those things were interacting to produce a different result. So...

KAYThey were compensating...

PAULThey...

KAY...to some extent.

PAULYes. It's not going to have...

KAYInteresting.

PAUL...the same affect in every woman. So that's why I decided, you know, nine months, two kids I can -- not knowing what the affect of alcohol will be, I can skip it for nine months.

KAYJanet, what's your advice?

DIPIETROMy advice is that you shouldn't be an alcoholic during pregnancy. We...

KAYOr at any time.

DIPIETRO...or at any time for many other reasons, and that has clearly toxic effects. It causes extreme mental retardation. But the truth is that particularly in the second half of pregnancy alcohol, taken in moderation, is not going to affect the developing fetal brain. And by moderation I mean a drink or two. And there's fairly substantial data to indicate failure to find any effects on child development. Now, we can't measure every single aspect of child development, and we don't know if particular fetuses might be affected, as Annie says. But women who had a couple of drinks should really not worry about that. We've over interpreted that message in many ways.

KAYLet's talk about smoking. And in a way the kind of control group that we had for smoking during the 1950s and 60s, when so many women did smoke during their pregnancies and they didn't know at that time that there could be a detrimental effect, reminds me a little bit of the control group of the women in Holland in the blockade who were starved. So we have this big group of women. What has been the impact of them smoking, all those women in the '50s and '60s who smoked? Can we know what the impact has been on their children today?

DIPIETROSo we know a lot about smoking and there's some excellent recent studies on it. Now, the first thing about smoking is smoking during pregnancy causes a smaller baby. We know that for sure. We've known it for a long time. The open question is -- and people may read this in various public media reports, that smoking causes ADHD in children. And we now know that that's really not true. And we know it be two very clever study designs. They look at families who have more than one children (sic) , and cases where the mom smoked with one pregnancy and not with the other. There's no differences in rates of hyperactivity, ADHD.

DIPIETROAnd we also know it from a study on women who had assisted reproductive technologies and they were implanted either with their own genetic material or with a surrogate's. And in those cases the women who had their own genetic material, there was a link with smoking. Women who had another -- other genetic material, there was no link. So you have to be careful when you read any study about prenatal effects. That the prenatal exposure, the smoking, the drinking, the stress, the anxiety, when you see associations later on, that it's not simply an inherited genetic effect.

KAYSo even though those babies are born small, the babies of smokers are born small there may not be a long term health issue.

DIPIETROOn the brain...

KAYOn the brain.

DIPIETRO...which is what my area of study on the development of the child.

KAYOkay. Let's go to the phones now to George in Sarasota, Fla. George, you've joined "The Diane Rehm Show" to speak to Annie and Janet.

GEORGEHey, great show.

KAYThank you.

GEORGEHere's my question. It sounds like that this epigenetic influence is most profound early in pregnancy, so I can understand how these switches -- these gene switches get turned on and off based on the fetal environment. But I thought I heard the doctor from Johns Hopkins say that the earlier in pregnancy the more persistent these epigenetic effects. So my first question is, does that mean that through the life of the person the epigenetic influence becomes less? And then my second question is, are those epigenetic changes that occur during a person's life transmitted then to the next generation, so that is there a vertical transmission?

KAYVery interesting. Janet or Annie, which one of you would like to take that?

DIPIETROLet me take the first part of that question. And I didn't mean to imply that the epigenetic findings in early pregnancy are the most persistent. What I meant is that exposures in early pregnancy are the ones that are most likely to have long term effects. Because in the first eight or nine weeks when the embryo is developing all of the organ systems are forming at that time. And something that knocks that off-track is going to have long lasting consequences. Whereas later in gestation when all those organ systems are relatively set, the ability for negative factor to knock the trajectory off is much less.

KAYAnnie.

PAULWell, that second question about can epigenetic changes be transmitted to successive generations is a really good one, because that is kind of a cutting edge area of scientific research right now. There's some preliminary human evidence, but I think, you know, mostly we're looking at animals right now and there's a really interesting experiment by a University of Washington scientist named Michael Skinner, who exposed a rat in one generation -- pregnant rat in one generation to some commonly used fungicides and pesticides. And found that her offspring had many health problems apparently as a result of the exposure to this chemical. But then their offspring and the offspring of the offspring, so that they also had these health problems having never directly encountered the chemical themselves. It was really only the great-grandmother, you might say, in this rat family who was exposed to these toxic chemicals. And yet the effects were seen down three or four generations.

KAYAnd can one womb have different environments at different stages of a woman's life, Annie?

PAULYou mean when they're gestating -- when a woman is gestating different children?

KAYRight.

PAULWell, there's a really interesting experiment that looked at exactly that, looking at whether part of the tendency to become obese is programmed in the womb. And the design of the experiment there was to look at women who'd had successful anti-obesity surgery.

KAYAnnie Murphy Paul is the author of "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives." And we're also joined by researcher Janet DiPietro. You can have more of your questions and comments after this short break. The phone number's 1-800-433-8850. Stay with us.

KAYWelcome back. I'm Katty Kay of BBC World News America sitting in for Diane Rehm. I'm joined in the studio by Annie Murphy Paul. She's the author of "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives." Janet DiPietro from Johns Hopkins School of Public Health is also here. We'll be taking your calls and questions, of course. The number is 1-800-433-8850 and let's go to Jennifer in Flagstaff, Ariz. Jennifer, thank you so much for joining "The Diane Rehm Show."

JENNIFERHi. My question is about hyperemesis and autism. During both of my pregnancies I had extreme hyperemesis and during the first one I resisted taking the drugs until I lost about 14 pounds from my pre-pregnancy weight. And when my daughter was diagnosed with autism the first thing I wondered was if that could have affected it. Have you encountered that anywhere in your research?

KAYJanet.

DIPIETROSo...

JENNIFERHello?

KAYYes. Janet's going to answer your question, Jennifer, please stay listening.

DIPIETROJennifer, I get literally weekly e-mails from individuals like yourself who have a child with a problem of any kind and the mom is always trying to search for what she did to cause this. And you should know that what you did taking the drug, not taking it, having hyperemesis, not having hyperemesis is not related to your child's autism. Autism is a complicated disease. It has a large genetic component. We're only now learning about the sort of epigenetic aspects of it. But women have this overwhelming need to find a cause for something that is not your fault.

KAYJennifer, does that help hearing that?

JENNIFERWell, some of my worry is I had it with both children and my one-year-old seems fine so far but my older daughter seemed fine at one as well. So it just...

DIPIETRORight. So I would say you...

JENNIFERYeah. And I definitely see it in my family. I know that -- I can see that there is a genetic component, too. I just -- I've heard a lot about switching genes on and off and I just wondered if, you know, if there's -- anyone has looked at any of those things.

DIPIETROSo hyperemesis, which is excessive vomiting, is not an uncommon symptom in pregnancy.

JENNIFERUm-hum.

DIPIETROAnd there's no reason to think that the exposure to the medication caused the autism. Autism is a very complex disease and you will -- I think you will probably, no matter what we say here, think that -- that you had something to do with it forever, but you didn't.

KAYJennifer, does that help?

JENNIFERI -- it does. I guess what I -- I mean I understand the genetic component and everything. I just wondered with you talking about switching genes on and off if -- you know, because I had extreme weight loss, too, because of it before I took the medication. And just listening to your program I suddenly had this anxiety again of, like, oh, could that -- could that have affected it. But...

KAYJennifer, I should tell you that...

JENNIFERBut thank you. I appreciate you taking time to answer my questions.

KAYAnd, Jennifer, I should tell you that Janet is sitting here in the studio and she is shaking her head. You did not cause your child's autism is what she's saying. That what you did did not affect the fetus in that respect. So I hope that that message is coming through, Janet.

DIPIETROSo this is a very natural feeling that people develop and so consequently when women ask me things that they're worried about oh, should I dye my hair during pregnancy, things like that. My -- that are unlikely to have any long term -- any consequences at all I tell them if you're worried about it that much don't do it not because I think it's going to hurt the fetus but I think if you have -- if you observe anything unusual about your child or your pregnancy outcome you are always going to blame that incident and...

KAYAnd they don’t need to.

DIPIETROAnd they don't need to.

KAYWe have an e-mail here from Pamela who writes to us, "Does this body of research illuminate the pattern that I've heard of that babies born in certain seasons and months of the year have greater longevity on average than bodies born in other seasons and months of the year?" Annie, is this anything that you've come across in your research?

PAULYes, yes. I write about that in the final chapter of the book which is about birth, it ends with the birth of my child. And I explore this season of birth effect in part because I see it as a really interesting analog to astrology -- something that -- that human beings have believed for millennia that when we're born has some affect on our well being, our health, our character, our personality. And that there's --there are some small effects that you can find that actually support that. And this longevity piece that the caller is -- the writer is talking about that has been found in studies, for example, of Civil War soldiers. So we're looking at people who lived, you know, 150 years ago.

PAULAnd -- and the finding there is that people who are -- let me see, born in the spring lived longer than -- than those who were born in the fall and winter. Or maybe it was the other way around. But the idea was that women who had nutritional deficiencies during difficult winters or who had respiratory infections when they were pregnant, which are obviously more common in the winter and spring, they gave birth to babies who were perhaps less robust than babies who did not.

KAYRight.

PAULSo -- but those kinds of conditions -- now when we have supermarkets open 24 hours a day and, you know, good drugs to help us with -- and vaccines to help us with illnesses that -- those kind of season of effects -- season of birth defects we don't see them nearly as much.

KAYBut it wasn't as simple as saying you were born in a season and if it was summer you were born more summery by personality. It was to do specifically with a medical condition of the winter and the respiratory issues.

PAULIt had to do -- even though we're talking about birth it had to do with pregnancy -- with what happened to the mother during pregnancy.

KAYRight. Let's go to Louis in Miami, Fla. Louis, you've joined "The Diane Rehm Show."

LOUISHi, how are you.

KAYGood, thank you.

LOUISI -- I'm just calling to make a comment. We adopted our son one week -- he was one-week old right out of the hospital. The biological mother used cocaine during the pregnancy. She also smoked a pack of cigarettes a day. And we know that she did use some alcohol but our son is absolutely flourishing. He's two and a half years old. He said his alphabet when he was two years and three months and one week old. And I'm just wondering are we lucky? We spent an awful lot of time with him reading and making -- letting him experience new things and exciting things and I -- I'm just wondering are we just among a few lucky parents having -- having him go through what he went through?

KAYOK, Janet, is Louis lucky?

DIPIETROI think you're son is lucky, Louis, to have parents like you. And the cocaine hysteria that we experienced in the '80s and '90s was just that. It was a hysteria. The image of a crack baby turned out to be a myth. There was not data to support it. There has not been any subsequent data to support that cocaine -- crack cocaine exerts a negative effect on the developing brain, infant or child. The alcohol use depending on how moderate or heavy may or may not have some influence but the important message that people who are interested in adopting children from whatever circumstances need to know is that early adoption -- moving a child, regardless of whatever biological vulnerabilities they have, into a normal, happy, nurturing social environment will compensate in terms of the development of the brain in those early years of life for any minor insult that a biological event during pregnancy might have had.

KAYAnnie.

PAUL(clears throat) Yes. And I'm just thinking about Janet's comment that it's actually the -- the caller's son who is lucky because what I try to say in "Origins" is that it is the case that prenatal influences can point you in a -- in one direction or another. They can -- the metaphor I use is it can dig a canal to make the water flow downhill one way -- more easily one way than another but that post-natal influences are enormously important also. And we can channel -- we can dig a new channel or dig a new channel for our children by doing everything that this caller is doing, you know, providing every kind of stimulation and exposure that he can. And, obviously, in his case he's doing a little bit of changing destiny with his -- with his adopted son because he's correcting for whatever the baby may have missed when he was -- was in utero.

KAYWe've talked about smoking, drugs and alcohol. You write also about food in your book and you describe a scene where you were walking through a grocery store and you said it was like going through a mine field, Annie.

PAULRight, right.

KAYI remember that, too. Endless people saying to me you should eat this. You shouldn't eat that.

PAULUm-hum.

KAYHow -- how complicated and how difficult it is...

PAULUm-hum.

KAYAnd how much should we be listening to all of those voices?

PAULUm-hum, um-hum, um-hum. In fact it was even worse than that. I had realized that I was pregnant when I was in the supermarket and I looked at the supermarket cart that I had filled with sushi and beer and all the good things I like to eat as a childless person. And actually pushed my cart back to the beginning of the opening of the store and started over again. And -- but I found it totally perplexing to know what was safe and what was not. And I...

KAYAre there things that are specifically not safe? I mean are there things that we now know we should not be eating during pregnancy that it's very clear about?

PAULSure, yeah. It's very clear that we shouldn't be eating fish that's high in mercury. But that doesn't mean that we should avoid seafood. I think that's -- often these things get drawn in black and white terms.

KAYOr necessarily sushi.

PAULYeah. There's a whole range of -- of food safety issues that come in here. You know, raw cheese -- unpasteurized cheese and undercooked meats and, you know, I think all those things are important to pay attention to. You do want to be careful. But I also think that I try to introduce in my chapter about food and origins a different perspective which is, you know, the fetus, especially in the later stages, can taste and smell and experience much of what you eat.

PAULIt's -- you are initiating your fetus into the culture of food that you -- that you participate in before he or she is even born. And there may even be an evolutionary adaptiveness to this. So you're teaching your fetus what's safe and good to eat. You know, you're telling the fetus a story in a sense. And so if we can think of eating during pregnancy as sharing and teaching rather than this frightening gauntlet that we all have to run, you know, just to avoid doing irreparable harm to our -- to our children. I think we can enjoy pregnancy and food a lot more.

KAYI'm Katty Kay. You're listening to "The Diane Rehm Show." And if you'd like to join us please do call 1-800-433-8850 is the phone number. Let's go to Susan in Tampa, Fla. Susan, you have a question.

SUSANYes, I do. I heard you say that there was really no relationship or maybe a -- even a good relationship between normal everyday stress that women experience and the outcome for the baby. And my question is what if the mother is under extraordinary mental and emotional stress that most women don't experience due to events that happen during that time. What's -- is there any research for the outcome for the baby?

KAYOK. I'm going to repeat Susan's question because the line was not very clear. Susan was asking whether having extraordinary mental stress or distress on the mother during pregnancy has an impact on the fetus, Janet.

DIPIETROSo my -- the short answer is we don't know but it's not particularly likely as much as people would like to believe it. And you have to think about -- that the prenatal period is not a different period from the postnatal period in terms of the woman. So women who are under a great deal of stress prenatally or have very anxious personalities prenatally or are depressed are often depressed after birth or have a lot of stress after birth. And we know that the way that depressed women or nondepressed women treat their babies is different and that the babies develop differently because of how they're parented.

DIPIETROSo it's very hard to design a study to answer the question that you're asking, looking at women who only had prenatal stress but not postnatal stress. But from what we know of some very large events such as the World Trade Center -- when the World Trade Centers were collapsed there were actually pregnant women in the buildings who got out. That those babies as far as we know are developing normally and there weren't even effects on their levels of prematurity or birth weight.

KAYAnnie, how can a woman's marital status and what she eats influence the sex of her yet-to-be conceived child?

PAULUm-hum, this is a kind of -- one of the more far out reaches of fetal origins research which suggests that the sex ratio of babies -- the number of boys born versus the number of girls can be affected by environmental events. And, you know, your listeners might be thinking well, whether a fetus -- whether a baby is a girl or a boy is determined at the moment of conception so how -- how can that be? That's true, but when you consider the fact that only a relatively small number of fertilized eggs actually end up being a live birth there's a lot of opportunities along the way for some embryos and some fetuses to be -- to be lost -- to be not born and there may be a difference in whether more of those miscarriages are perhaps of male babies -- and that -- of -- of male fetuses. And that is what a series of studies have shown.

PAULI think we should, you know, be cautious in interpreting these -- these studies but they're interesting to hear about and to think about. That following very stressful events like an earthquake in Kobe, Japan, following the great smog the sort of -- the big smoke in -- as it's called in London when there was a blanket of smoke that -- that stayed on the city. Following events like those we see small declines in the number of boy babies born versus the number of girl babies. And the idea is that in very difficult, challenging times in our ancestral -- our ancestral environment it was a better bet to have a female who could -- who could bear you a grandchild that that was going to be less likely to happen if you had a boy.

KAYThe book is "Origins: How the Nine Months Before Birth Shape the Rest of Our Lives." Annie Murphy Paul is the author. I've also been joined by Janet DiPietro. Ladies, thank you very much for coming in to join me.

PAULThank you.

DIPIETROThank you.

KAYI'm Katty Kay of BBC World News America. You've been listening to "The Diane Rehm Show." Thanks so much for listening.

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