Biological sex is usually described in simple binary terms: male or female. This works well for germ cells (sperm versus eggs), but for other body organs it is of little help. A new study by the Max ...

Tiny male spiders of a species common to the southeastern United States routinely remove one of their two oversize external sex organs. It’s an extreme act, but one that apparently enables them to run ...

Human genitalia evolved through development which has been chronicled by a team of researchers from Harvard University. Male snakes and lizards each possess a pair of penises, which evolved from ...

Male genitalia, both internal and external, is made of many components. The testes are an important internal component, and the penis is the main external part. The male genital system consists of ...

The correct development of two distinct sexes from a sexually undifferentiated, bipotential embryo is a multi-step process that is essential for mammalian reproduction. Disorders of sexual development ...