Modern geneticists no longer use these familiar symbols and instead rely on a square (for male) and circle (for female): This symbolism was developed by Pliny Earle, a doctor with the Bloomingdale ...

Intersex people may present physically as male or female but in fact have neither XY nor XX chromosomes. They may instead have a mix such as XXY.

How is sex determined using chromosomes? You might remember learning in high school biology that all the genetic information in the human body is packaged into 23 pairs of chromosomes.

For the first time scientists have created two lines of human cells that are identical aside from their sex chromosomes: one has XX chromosomes, and one has XY. This unique set of cells could help ...

Intersex people are born with genitals, chromosomes, or internal reproductive organs that don't fit typical male or female patterns and may not match their sex assigned at birth. Find out more.

"Nobody is male or female at fertilization," says Dr. Eve Feinberg in response to Trump's executive order that claims a person's sex is decided "at conception." ...