by LROBBINS » 13 May 2021, 17:56
I'll not argue the politics, but will point out that the genetics is not as simple as XX=female, XY =male, though that is the usual case.
Though individually fairly rare, there are individuals who are XXX, XXY, XYY, X0 and others who are mosaics with some cells one thing, and some another - altogether these anomalous chromosomal constitutions are not near as rare as you might think. Moreover, it's not the chromosomes themselves that determine sex, but the genes they carry and the interactions of those genes with genes on the autosomes (non-sex chromosomes) that determine both the sexual developmental process and the eventual sexual physiology, and as with any genes these can carry various mutations - again, individually pretty rare, but summing all the variants, more common than one might think. In most cases, one doesn't know, and we don't have the tools to find out, why some people have a "mismatch" between their chromosomes, or even primary or secondary sexual features, and their sexual identity, but in some cases it is known, sometimes quite precisely. The first one clearly demonstrated was for X0 individuals, but some of the more subtle ones now, with ever improving genetic and molecular technology, have clear causes too. In general, whether the underlying cause is known with precision or not, however, it's NOT a matter of choice.