People who have one of several well-documented medical conditions do not have only XX or XY chromosomes, which typically correspond with female and male sexes, respectively. Those conditions include ...

Gene editing techniques may eventually allow trisomy to be treated at the cellular level, according to an in vitro ...

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.

A recent Trump executive order defines sex based on gamete size. But the order oversimplifies genetics, hormones and reproductive biology.

UCSF researchers found that brain cells age more quickly when they rely solely on the X chromosome inherited from a female's ...

Human biological sex is determined by the sex chromosomes X and Y. In most cases, females possess two X chromosomes, while males have one X and one Y. However, there is some evidence that the Y ...

One X chromosome is inherited from each parent and two are present in women at birth. However, only one X chromosome is required in each of their body cells, therefore the other is inactivated at ...