[omginternets]

That was my point, so we're in agreement. (I've edited my post to make it clearer).

Edit: on second thought, we're not so much in agreement as nothing is fully genetic or environmental. There are, for instance, cases of XY females. I'd agree if you said the genetic link was orders of magnitude stronger between genes and sex, but the "100%" perpetuates a common misunderstanding of genetics.

[justinjlynn]

Generally, individuals with the XY genotype but the female phenotype have an additional genetic anomaly which renders them androgen insensitive. Therefore, I would say that, in most cases, the sex of an individual is fully, or at least a fully as possible, genetic. It's just not as dependent on the presence of an X or Y chromosome as one would think.

I suppose you could induce something like that by treating an embryo with finasteride or another SARM but there's a reason such drugs are in pregnancy category X. They tend to produce wider ranging and more severe defects than just changing the sex of the embryo. Hormones are complicated.

[omginternets]

Fair enough, but then it should also be possible to environmentally affect gene expression. I'm clearly nitpicking insofar as sex is overwhelmingly determined by genetics, but I feel it's important to hammer in the point that "everything is nature and everything is nurture".