Gender and Sexuality  - Sensitivity

Sexuality and gender are complex things, and social attitudes about them have varied as long as humanity has existed. Many cultures have accepted a gradient between the poles of male and female.
And today, with the brain and genes' studies barely begun, we should at least understand that these complex systems change over your lifetime. From conception to death. Through puberty, middle age, old age and for women, pregnancy.
There may be periods of your life when you could procreate if you sneeze, and others when a miracle couldn't make it happen. Not for you anyways. Yet this is often why gay/lesbian and transgender people are oppressed by their families. And by their groups. They want more of you: a dynasty, an empire.

So many things could change and nothing is guaranteed.

Info on Intersex:
https://www.isna.org/faq/conditions
Info on transgender/sexuality:
https://www.ncdd.org/exchange/files/docs/gender_variance_model.PDF

In BDSM, some people like to play/manipulate/"force" gender variance on their partner.
And some people on their own like to cross-dress. Be sure you know the difference, and be sure you ask someone before you assume they are doing one or the other. Otherwise you could end up being really cruel to them.