Earlier this year, the often overlooked issue of differences in sex development came to the fore after two women boxers were allowed to compete in the Olympics after previously failing a gender ...

Human egg cells are often prone to chromosomal errors. As women age, the error rate increases sharply — and can contribute to infertility, pregnancy loss, and ...

In female mammals, one of the two X chromosomes is usually inactive and forms the so-called Barr body. The image shows a cell nucleus with the Barr body marked in green. Unlike men, who carry one X ...

Scientists warn that the human Y chromosome has lost most of its genes over millions of years, and new research suggests ...

Doctors in Brazil discover and confirm that a woman has blood with male chromosomes, a rare case of human chimerism.