Professor Lee Ellis and colleages at Minot State University N.D. have found that mothers of homosexual daughters used thyroxine and amphetamine in pregnancy at higher frequencies than mothers of heterosexual daughters.
The researchers found that the mothers of homosexual women were at least five times more likely to have taken synthetic thyroid medications during pregnancy than mothers of heterosexual women, and eight times more likely to have used amphetamine-based diet pills such as Dexedrine and diethylpropion.
They also found evidence that some drugs have the opposite effect during pregnancy, reducing the probability of homosexual offspring. Mothers of heterosexual males were 70 per cent more likely to have taken drugs to combat nausea than those of male homosexuals.
The effect of the drug use is most pronounced in the first trimester of pregnancy. Since it is generally believed that sexual orientation of the brain is set during the first trimester this aspect of the result is not surprising and it can even be seen as strengthening the likelihood that this result will hold up when a follow-up study is conducted on a larger number of subjects.
I predict that in the future as the influence of various drugs on sexual orientation become known women will intentionally use drugs to increase the odds that their children will be born with the sexual orientation that they prefer. Will lesbian women use sexual selection techniques to ensure that their offspring will be daughters? Also, will they choose to have lesbian or heterosexual daughters?
Since women are the one that carry babies in pregnancy and hence (at least in Western societies) women have a bigger say on what goes on in their bodies during pregnancy my guess is that female homosexuality will be selected for more often than male homosexuality will be selected for. I expect male homosexuality to become more rare once means to decrease its likelihood are identified. I am not sure whether female homosexuality will become more or less common. My guess is it will become less common as well.
For other work by Lee Ellis see my post Obesity Being Selected For In Modern Society?
Update: Given that amphetamines and synthetic thyroid hormone are products of mid 20th century industrial civilization this result strongly suggests that industrial civilization has caused a higher incidence of lesbianism.
What else has industrial civilization done to alter, on average, human biological development? Certainly drug abuse and alcohol abuse cause an increase in the incidence of an assortment of defects. Medicine is allowing more defective babies to survive pregnancy and early childhood. Medicine, public health measures (e.g. sterile water) and higher living standards (more food, better shelter) are also reducing the selective pressure caused by infectious diseases. What is that causing to be selected for instead? Chemical pollutants might be causing other changes that influence fertility, cognitive ability, behavior, and degree of masculinity and femininity.
There are two issues that need to be separated here: First, how are elements of modern environments (e.g. specific drugs, quantity and quality of food) altering development of individuals as reported above? Second, what changes in natural selective pressure are happening as a result of these changes and what genetic variations are being selected for or against? Both of those questions will get many more answers in the years ahead.
One point can be made about the above case: If being a lesbian reduces fertility (anyone know?) then any genetic variant that increases the likelihood that one will take amphetamines or thyroid hormone is (probably very slowly) being selected against. Also, any genetic variant which makes it more likely that a female fetus will become homsexual in response to amphetamine exposure or thyroid hormone exposure is also (again, probably very slowly) being selected against.
|Share |||Randall Parker, 2004 December 12 02:21 AM Brain Development|