"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).

Physical gender is not always just a matter of XX or XY, girl or boy. In approximately one out of every 100 births, seemingly tiny errors occur during the various stages of fetal sex ...

athletes with XX chromosomes — despite reports they may actually be men, who by definition have XY chromosomes. After Italian boxer Angela Carini ended a bout with Khalif after 46 seconds ...

"You either have XX or XY chromosomes," Rep. Nancy Mace, R-S.C., wrote Feb. 20 on X. "Those are the options." "You either have XX or XY chromosomes," Rep. Nancy Mace ...

"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).