This is just a quick review of an old study.
This study found that trans women (born male) and control males responded to estradiol in the same way. Specifically, they looked at how taking estradiol affected the levels of other hormones: testosterone, estradiol, lutenizing hormone, and follicle stimulating hormone.
The authors were attempting to test Dorner’s theory that gender dysphoria in trans women is caused by a defect in a normal imprinting mechanism of testicular testosterone on the hypothalmus. In other words, it might be that testosterone affects the hypothalmus prenatally, but something goes wrong with the process in trans women.
They conclude that if there is such a defect, it does not affect the levels of these hormones or the way they response to estrogen.
The study does not, of course, prove Dorner’s theory.
What I found interesting was that both trans women and control men responded to taking estrogen in the same way.
Study of the effect of estradiol on gonadotrophin levels in untreated male-to-female transsexuals by Goodman RE, Anderson DC, Bu’lock DE, Sheffield B, Lynch SS, Butt WR in Arch Sex Behav. 1985 Apr;14(2):141-6.