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.

Off a quiet hallway on the top floor of a building at the University of Osaka in Japan, Katsuhiko Hayashi is hatching a revolution. Human embryo science: can the world’s regulators keep pace? He is on ...

Scientists have created human eggs containing genes from adult skin cells, a step that someday could help women who are infertile or gay couples have babies with their own genes but would also raise ...