"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).

But that doesn’t always apply when it comes to categorizing people by their sex chromosomes. "You either have XX or XY chromosomes," Rep. Nancy Mace, R-S.C., wrote Feb. 20 on X. "Those are the ...

The X and Y chromosomes, commonly referred to as the sex chromosomes, are one such pair. They determine the biological sex, reproductive organs, and sexual characteristics that develop in a person.

For years, the fact that women tend to outlive men has been a topic of interest and speculation among scientists and the ...

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 ...

Scientists may have figured out why women live longer than men — linking it to having two X chromosomes, which defend against ...

the second X chromosome can have a protective effect and reduce the effects of a gene change on the first. However, when a person has XY chromosomes, that protective effect is lost. This is why ...