Mace’s claim ignores the existence of several ... or differences in sex development — cases in which someone’s anatomy does not fit into male or female — according to a commonly cited ...

"You either have XX or XY chromosomes," Rep. Nancy Mace, R-S.C., wrote Feb. 20 on X. "Those are the options." Most commonly, a person is born with two X chromosomes (female) or an X and a Y (male).