Surprising pattern: The genetic programmes responsible for the development of sex-specific organ characteristics in mammals are turned on almost exclusively late in the development of the organs, in ...

TOKYO (AP) — Japan’s Supreme Court on Wednesday ruled that a law requiring transgender people to have their reproductive organs removed in order to officially change their gender is unconstitutional.

For some parents, it’s one of the most exciting parts of being pregnant: finding out your baby’s sex. But what, exactly, decides a baby’s sex, and how does it all develop? Here’s your primer to what’s ...

Current debates over the fundamental nature of biological sex are not merely esoteric academic musings. They have direct implications for policy related to sex-based legal protections and medicine. It ...

Richard Dawkins, the celebrated evolutionary biologist, has recently used the claim that biological reality entails that sex is binary, to launch a broadside on the gender choices of trans people. In ...

The following outlines aspects of the female reproductive system, including the internal and external organs, the menstrual cycle, the egg, and reproductive hormones. The menstrual cycle is a monthly ...

A wave of pseudoscientific papers has tried to dismantle one of biology’s most fundamental truths: only two sexes exist, male and female. These papers often claim that sex is a broad “spectrum,” and ...

President Donald Trump issued an executive order defining the terms "male" and "female" based on whether a person belongs "at conception" to the sex that produces sperm or eggs. Neither sperm nor eggs ...