The most we’ve seen as plausible arguments are women hormone fluctuations during pregnancy causing disruptive development of the fetus.

Yup, and even then, there have been no consistent endocrinology studies to back up that point. If you surf through enough studies, you'll find that the actual premise for that is based on speculative conjecture: https://academic.oup.com/endo/article/152/8/2937/2457178

Basically, it's just guesswork that there might be some endocrines that might affect the orientation of a fetus. And this premise is based entirely on... theorycrafting.

I wish I was making that up.