Any two human beings, no matter how divergent their ethnicity, can produce a child. Provided that one of them is a man, and the other is a woman.
All human beings belong, not only to a single species, but to a single subspecies, with less biological difference between any two than there is between a Labrador and a dachshund. The differences that there are, have been changing constantly ever since they first began to emerge, since they have not always been there.
But the difference between the two sexes has always been there, and it is written into the chromosomes of every cell of the body, no matter how the tissue may or may not be cut up.
On the first of these realisations depends every past and future achievement of the anti-racist movement. On the second depends every past and future achievement of the women's movement.
There must be no compromise on either as a matter of political principle. There actually can be no compromise on either as a matter of scientific fact.
Yes, there are people who want to shut me up.