Can prenatal exposure to Diethylstilbestrol masculinize the gender-role behavior of girls and women?
1991 Study Abstract
This report concerns the role of prenatal hormones in normal and abnormal psychosexual differentiation.
Gender-related behavior development in females exposed to diethylstilbestrol (DES) in utero: an attempted replication, US National Library of Medicine National Institutes of Health, Journal of the American Academy of Child and Adolescent Psychiatry, NCBI PubMed PMID: 2005061, 1991 Jan.
Image credit RAZ Zarate.
Several studies indicate that perinatal treatment of infrahuman female mammals with diethylstilbestrol (DES) masculinizes certain features of their brain and behavior.
Accordingly, the authors have hypothesized that prenatal exposure to DES may also masculinize the gender-role behavior of girls and women.
A previous study suggested that prenatally DES-exposed women show decreased interest in parenting.
The authors failed to replicate these findings in a different sample despite the use of similar methodology.
Post-hoc analysis shows that the assessment devices would have detected masculinization if it were present.
The implications of these findings for an understanding of psychosexual development are discussed.
DES DIETHYLSTILBESTROL RESOURCES
- Studies on DES and gender identity and DES and psychological health.
- Diethylstilbestrol DES studies by topics.
This paper, like lots of others looking at the effects of DES on gender identity, is based on a false premise: that DES would induce brain masculinisation in girls. Female rodents who were prenatally exposed to DES show male like behaviour. The assumption was that the same would apply to human beings. In fact it doesn’t. This is due to an important species difference between us and rodents.
In rodents, the final trigger for masculinisation of the brain is the conversion of testosterone into estradiol, and the action of estradiol on estrogen receptors in the brain. That’s a quirk of biology peculiar to rodents though. In humans (and other primates) that final conversion step isn’t necessary, because brain masculinisation is instead driven directly by the action of testosterone on androgen receptors.
Under most circumstances this doesn’t make a lot of difference, and either way, it’s the males that end up with a male brain. However, when the developing foetal brain is exposed to DES, the effects are in rodents and primates are completely different. In rodents, the DES mimics estradiol and triggers male brain development, so the females end up with male brains. In primates, DES doesn’t have any direct effect on the sex of brain. However, it has an important indirect effect: DES acts as a chemical castration agent, and suppresses testicular hormone production (including the production of testosterone) in doses well below those being used for miscarriage prevention. Without testosterone, masculinisation of the brain doesn’t occur, and brain development goes down the (default) female pathway instead of the male one. I think that’s why many DES “sons” have ended up with a female gender identity, and many more of us have problems with abnormally low testosterone production (hormone production is controlled by the brain).
Basically, it means that all the research looking at the effects of DES on behaviour, sexual orientation and gender identity, has all been looking in completely the wrong place: for masculinising effects in DES daughters instead of feminising effects in DES sons.
Well, first, thank you for your in-depth comment. Then, regarding this topic and FYI, there are studies on other species – such as rhesus monkeys – which found similar results. Personally, I have witnessed such effects on (human) 3rd generation (female). I’m not sure (at all) it’s a pure coïncidence. Finally, as you know, I managed to find lots of papers in ref to the feminising effects in DES sons, all listed on this webpage : DES AND GENDER IDENTITY STUDIES. I hope this will help, cheers,