Interesting comments from Dr. Will Powers, who specializes in trans medicine:
“Approximately 20% of my transgender women (Male to Female) and 85% of my transgender men (Female to Male) have considerable hormone abnormalities which deviate more than 95% from “average” values.
20% MtF (Elevated Estrone/Estradiol/Free Estradiol/SHBG, Low FSH/LH, very low T/DHT)
85% FtM (Massively elevated androgens in one or more categories, Androstenedione, Androstanediol, Androsterone, DHEA-S, Testosterone or DHT (Or a normal testosterone with a massively elevated free T due to a near lack of SHBG)”
“I have lots of kids come to me that have hormonal disruption that I fix and then they no longer feel trans. This is most commonly done with my patients in FtMs. They come in with some insane androgen level, I fix it with drugs, and then they no longer feel like they want to transition.
I have never seen this work in someone over the age of twenty-five, but the younger they are, the more likely they seem to change their position on taking hormones once the underlying dysfunction is corrected.”
The Rationalist Conspiracy 
Interesting. I also had significantly elevated estradiol before I started HRT. I was well over 25 though.