I don't feel that I can say that a way a person acts or what clothes they wear or what sexual preference they have defines maleness or femaleness. That would be lead to inflicted definitions of who people are.
What I do know is that there are two, consistent, stable, identifiable biological genders. This is not an inflicted definition, this is a just an observation. All of the animals on our branch of the evolutionary tree have had two and only two biological genders with, so far as we know, X and Y chromosomes. Again, that's just an observation of how the natural world is.
If we are the physical products of evolution, so are we the social products of evolution. But this has no ethical implications. It doesn't say anything about how people should or should not act. There's nothing normative about observing how we have developed.
boddi