"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).

XYY syndrome affects 1 in 1,000 males and is caused by the presence of an extra Y chromosome. XYY syndrome symptoms vary but males with the disorder could be taller than average, have speech ...

Biological sex is all over the news lately. Whether it's via President Trump's executive order affecting passport policy, ...

I gave birth to a beautiful baby girl with almond shaped eyes,” a woman named Sarah wrote on Cincinnati Children’s Hospital’s website. “The doctors and nurses didn’t notice, but I did. After days of ...