Humans don’t have a defined mating season like deer or wolves. Here’s how evolution blended biology, culture and social life into year-round intimacy.

As commercial spaceflight edges closer to reality, astronauts spend more time orbiting Earth, and as we look to one day settle on Mars, questions about sex and reproductive health in space need to be ...

As humanity moves from brief space missions toward longer stays — driven by commercial ambitions for moon bases and eventual Martian settlements — scientists are beginning to confront how the ...