You and I have done parallel research, but not using the same sources. It has been known for some time that having gender dysphoria has three components. They are your identity, which you refer to as gender identity, your presentation, or the way you interact socially, and your sexuality. The three can be completely unrelated. You can have a female identity, but have no sexual orientation towards males. As you correctly noted, homosexuality is also hardwired. To take it a step further, most experts, believe that transitioning does not affect your sexual orientation. Whatever you like before you transition tends to stay the same after you complete it according to this group. My experience has been somewhat different. When I thought I was a male (primarily because my parents had the same expectations as your father), I would have considered myself a traditionally heterosexual male. I liked women. It was a surprise to me to discover that when I accepted my identity, I very quickly developed an interest in men and had an almost irresistible urge to be with one. Was this something I had hidden my whole life? Or was it something related to my transition? I have decided it’s not really important.

One of the reasons that your identity and sexual orientation can be different than your physical characteristics is that fetuses develop at different rates during gestation. Sexual characteristics are established early in the process, beginning around four weeks. Brain development does not occur until 10 weeks or later. In between many things can happen to create a disconnect between physical characteristics, and gender identity and sexual orientation. The latter two seem to be fixed as the brain develops later in the pregnancy. Does that make a difference in terms of identifying who is trans or who is not? Of course not. Gender identity exists on a spectrum as you correctly identified. Sexual orientation can as well, but both seem to be a matter of fetal brain development primarily and at times unrelated to physical development. Looking specifically at homosexuality, researchers suspect that the presence of high levels of cortisol in the developing fetus’s mother because of high stress levels may be a significant factor in same sex orientation, especially boys. There is a lot more we could discuss, but then we would end up writing treatises to one another.

The important thing I think, is that your identity has may have little to do with your sexual orientation. They may or may not be congruent. At the end of the day, however, orientation of trans people should not even enter into the process of helping to identify who may be trans. Both are brain phenomena, but are independent issues. We treat trans people medically and surgically to help them overcome their dysphoria, which is primarily a mismatch between physical characteristics and gender identity. What their tastes may be in the bedroom really has nothing to do with it and should not be part of the discussion.