Molecular mechanisms of sexual development.

Gonadal cellular organization is very similar in all vertebrates, though different processes can trigger bipotential gonads to develop into either testes or ovaries. While mammals and birds, apart from some exceptions, show genetic sex determination (GSD), other animals, like turtles and crocodiles, express temperature-dependent sex determination. In some groups of animals, GSD can also be overridden by hormone or temperature influences, indicating how fragile this system can be. This review aims to explain the fundamental molecular mechanisms involved in mammalian GSD, mainly referring to mouse as a major model. Conceivably, other mammals might show a molecular mechanism different from the commonly investigated murine species.