Biology addresses sex, not gender (whether ascribed gender or gender identity), and there are vastly more than two ways in which the various biological attributes grouped under “sex” line up; which is why when (as is, to be sure, quite common) binary sex distinctions in biology and medicine are used they are drawn differently in different contexts.

I mean, there's documented cases of non-chimeric fertile females (in the sense of “people who produce ova and can reproduce with people who produce sperm”, which isn't the only biological definition of sex but is the one most relevant to fertility and reproduction) with 46,XY karyotype and normal male coding sequences in SRY and other genes associated with sex determination. Simplistic generalizations about sex and biology, aside from having dubious relevance to gender discussions, are pretty invariably factually wrong.