Claims spread that definitions of "male" and "female" included in a January 2025 executive order that asserted sex is established at conception accidentally classified all Americans as women. The ...

The cellular biology of reproduction is often depicted as an epic journey, in which millions of intrepid sperm fight to be the first to claim the ultimate prize: the chance to fertilize the egg, which ...

I’ve long been fascinated by one of the most stubborn patterns in biology: males and females rarely live the same length of time. In humans, women nearly always outlive men, with an average advantage ...