This article from Scientific American magazine discusses the hormonal differentials in early ( first Trimester ) pregnancies vis a vis gender. It doesn’t dive into altering the natural course of things, only what is indicated at various weeks of gestation.
So. Can a pregnant woman, by taking very measured amounts of hormones pre-pregnancy and into the first trimester, guarantee the gender of her baby? And along with that, would she be guaranteeing that the child would not be a transgender person when born?
IF, in fact, gender identity and not just biological body parts are formed in those early weeks, would purposeful raising or lowering of hormones more firmly guarantee gender?
I’m NOT advocating Eugenics, which is what this question is about. The idea is horrific to me. That said, I don’t know how to do the Googling to find a scientific answer to the question.
The biological pathway which changes the default female developmental pathway to a male pathway starts with activation of the SRY gene, which is normally carried only on the Y chromosome. The gene makes a protein which triggers a series of events perhaps best analogized as a biological Rube Goldberg machine which results in male development.
Along the way hormone and hormone receptors are involved. Deficiency or excess of either hormone or receptor can confuse the process resulting in one of many disorders of sexual development. As the activity of these hormones and receptors are specific to location and time it would be practically impossible for a mother to take a pill or injection and thus alter the gender development of her fetus. She just could not get the right dose to the right place at the right time given our current technology.
Iggy - BS Genetics, worked in Endocrinology and Reproductive Physiology lab
That said… it is true that sometimes a person with XY chromosomes can outwardly display typical female features. Or someone with XX chromosomes can rarely outwardly display typical male feature. There are a great assortment of disorders of sexual development and they really are not that rare overall. Some make relatively minor changes to outward appearance, and others make larger changes.
So when some conservative commentators such as Ben Shapiro try to make broad statements equating chromosome karotype with gender they almost always leave out critical details. XX results in female phenotype most of the time, but not all of the time. XY results in male phenotype most of the time, but not all of the time.
That’s fascinating. I wonder how much grief could be avoided if schoolbooks would just phrase it as: “XX results in female phenotype most of the time, but not all of the time. XY results in male phenotype most of the time, but not all of the time.”
The OP isn’t asking about phenotype but rather about gender, though, right? So I’m not sure that the question has been answered. Setting aside the question of a woman’s ability to control the development in utero, is there evidence connecting gender to hormone levels at all?
Perhaps the broader question is whether we know the genetic or physiological basis of gender.
