Is transgender just the tip of the iceberg with "birth identity" issues...
I'm curious if someone could be trans-racial/trans-species?
All zygotes start out the same. Then later on various hormones start differentiating between male and female. It is obvious how hormones affect the genitalia, but we also know that sometimes genitalia misform. Sometimes the genitalia does not match the chromosomes. Hormones also have an effect on the developing brain. Brains get wired in different ways. We're only starting to understand the role these hormones have on various traits.
Let's look at three traits: gender identify, sexual orientation, and masculine vs effeminate. It seems that none of these are binary, yes/no or 0/1, that they each can be a spectrum. You can be mostly gay or mostly straight, or something in between. You can feel very much like a girl or a boy or something in between. And you can be hyper masculine or quite effeminate or something in between.
And that the three can be completely unrelated to each other. There are effeminate straight guys, and butch straight girls. As well as masculine gays and feminine lesbians.
Now to your question of race and species. Race is a social construct. The definition of race has changed over the years. Not that long ago southern Europeans were considered a different race than northern Europeans. There are no biological differences between the races. There are different cultures, and you may find yourself relating more to a culture you were not raised in, but culture is not genetic or hormonal.
As far as trans-species, I suppose it is possible for some long abandoned genes to pop up. I certainly have met people who seem to be a bit Neanderthal