I've no doubt that the studies were "cherry picked", given that she wanted me to be able to understand it, obviously wasn't going to pick studies that refuted the possibility, and having a vested interest in reading about the phenomena and seeing how it can be biologically explained would also have read a much broader range of literature on the topic than me and so would pick the ones she thought best explained the way in which gender dysphoria could develop. I don't see that as a reason to presume the studies and journals in which they were originally printed must be disreputable.
I'm not going to get into a google scholar search (I imagine this could be time intensive given that I don't know the buzz words, and having done enough scholar searches in the past I know what a pain choosing the appropriate terminology can be to find the right articles and subsequently having to wade through), but it was easy enough to find the NHS page on gender dysphoria:
www.nhs.uk/Conditions/Gender-dysphoria/Pages/Causes.aspx
^"In rare cases, the hormones that trigger the development of sex and gender may not work properly on the brain, gonads and genitals, causing variations between them. For example, the sex (as determined physically by the gonads and genitals) could be male, while the gender (as determined by the brain) could be female.
This could be caused by additional hormones in the mother?s system or by the foetus?s insensitivity to the hormones, known as androgen insensitivity syndrome (AIS). In this way, gender dysphoria may be caused by hormones not working properly within the womb."^
They seem to be saying more eloquently what I was trying to put across before. I'd imagine they wouldn't be saying this if there weren't reputable studies already conducted to indicate this could be a possible cause.