The male reproductive system has two testes (singular ... giving insight to the human body and its capabilities. BBC Teach has thousands of free, curriculum-linked resources to help deliver ...

One of the most fascinating aspects of human life is how we choose ... on strategies for maximizing individual reproductive success. Aa Aa Aa A mating system describes how males and females ...

MONTGOMERY, Ala. — The Alabama Senate Thursday approved a bill defining “sex-based terms” strictly based on biological sex.