It doesn't make any sense for someone else to tell you who you are. How could they know? Of course, if you were autistic or schizophrenic, that would be different...
Anyway, I remember reading an evocative description by a trans man of how testosterone made him feel like a sex crazed monster. Nobody can know for sure if they have the same experience, just like we don't know if the color blue is the same for us.
But it seemed to me that implied one of two things - either he was experiencing what cis males consider normal, and it was horrifying, in which case it was evidence against him being "really" male, or else he was not experiencing what being a cis male is like, in which case it was evidence that administering male hormones may not produce the effect of natural ones.
The goal of trans hormone therapy is to reverse the effects of the hormones of the person's biological sex, so HRT dosage of e.g. testosterone is usually more than the average cis man would produce. It's possible that that much testosterone was too much for the person you mentioned to handle, especially for his body not being used to it, or that he just got prescribed for more than he should have taken. (He could've also gotten it from the black market, in which case it would almost definitely be an incorrect dosage.)
Also mirrored by the fact that other cultures do not experience this issue so acutely.
The freer and richer women are, the more likely they are to be found in stereotypical fields.
You can really interpret the prevalence of trans women in programming as being related to nurture or nature. The data point in a vacuum doesn't obviously point to either conclusion.
There are still many women among those who program mathematics (statisticians etc), just that they are usually not called programmers. Also there is much less demand for people who can program math than people who can glue together libraries and create crud apps, so even if all math programmers are included in the statistics they would get dwarfed by the app programmers.
Source of the combination mathematics and statistics being a gender balanced field, above 40% women: https://www.nsf.gov/statistics/2017/nsf17310/digest/fod-wome...
Engineering always being male dominated, around 15% women: https://www.nsf.gov/statistics/2017/nsf17310/digest/fod-wome...
Computer science gender balance getting lowered to engineering levels: https://www.nsf.gov/statistics/2017/nsf17310/digest/fod-wome...
We're women because we say we are - and that's really all there is to say about it.
We are disproportionately into things like coding because, growing up, the vast majority of us are socialized the same way as boys would be. Amazingly, it turns out that in a vacuum, the activity of programming a computer isn't actually gendered.