[Understanding and treating male infertility : a medical and public health challenge].

Infertility affects nearly one in six couples and involves a male factor in about 50 % of cases. Its causes are varied, including genetic, anatomical, hormonal, infectious, environmental, or iatrogenic factors. Diagnosis is based on medical history, clinical examination, semen analysis, imaging, hormonal assessment, and, when necessary, genetic testing. The treatment depends on the underlying cause and may range from lifestyle modifications and hormone therapy to surgery, as well as assisted reproductive technologies, such as in vitro fertilization and intracytoplasmic sperm injection. Early and multidisciplinary management significantly improves the chances of achieving parenthood.