A controversial new book written by Dutch neuroscientist, Dr. Dick Swaab, We Are Our Brains, claims that women who admit to smoking during pregnancy or who are under a great deal of stress are more likely to produce gay children.
The Amsterdam University professor’s suggestion that a mother’s lifestyle during pregnancy is linked to the health of her developing fetus is nothing new, but the idea that nicotine exposure in utero resulting from smoking mothers is somehow able to impact the developing fetus’s sexual orientation is certainly a controversial claim.
Swaab cites a number of studies in his book in support of his claims. One such study has led Swaab to the conclusion that somehow “Pre-birth exposure to both nicotine and amphetamines increases the chance of lesbian daughters.”
Another of the cited studies purports to demonstrate that a group of mothers given synthetic estrogen during pregnancy to reduce the risk of miscarriage gave birth to an unusually high proportion of daughters who eventually grew to identify as either lesbian or bisexual when compared to a group of mothers who did not take the synthetic hormones.
Swaab also claims that women who experience high levels of stress during pregnancy are more likely to give birth to both male and female children who will later identify as gay because they are exposed to increased levels of cortisol, a stress hormone, in utero that affects the production of their own fetal sex hormones.
The professor even reportedly suggests that boys born to mothers having already given birth to older brothers have increased odds of being gay. The study he cites in support of this premise offers the explanation that this may be due to the development of increasingly stronger responses to male hormones in the mother’s immune system as each boy is carried.
In addition to his claims that smoking and stress while pregnant are linked to having gay children, are a number of other claims about the ways in which the mother’s lifestyle during pregnancy might influence her developing fetus. Most of these are decidedly less outlying and controversial than his claims about the links to sexual orientation.
Dr. Swaab also suggests that drinking during pregnancy is ill-advised. His book suggests that both drinking and taking drugs during pregnancy have been linked to lower IQ in the resulting children later in life. He states that “In women who drink a lot, cells that were meant to migrate across the fetal brain can end up leaving the brain altogether.” He says that there is no amount of alcohol that can be consumed safely by pregnant women, and that lower IQ and hyperactivity have been seen even among children born to mother’s who claimed to have consumed just one alcoholic drink per day during pregnancy.
Weighing in on autism, Swaab reports that mothers who live in areas of high pollution are more likely to give birth to children who receive the diagnosis as they grow older.
Swaab reports that fetal brain development begins as early as two weeks into pregnancy and that any exposure to toxins from that point forward has the potential to impact that development.
Though Dr. Swaab’s claims that things like smoking and stress during pregnancy may seem a bit “out there” and are certainly controversial, he does not claim that a pregnant mother’s lifestyle is entirely responsible for the development of certain traits later in life. Overall, he suggests that the “lifestyle factors” are a relatively small factor on child development with genetics playing a large part.
By Michele Wessel