Which hormone develops the primary male sexual characteristics?

• A. Testosterone
• B. Estrogen
• C. Progesterone
• D. Growth Hormone

Answer: (A)

Testosterone is the primary androgen that drives male sexual differentiation and development. It is produced by the testes and triggers the formation of male internal reproductive organs from the Wolffian ducts, and, after being converted to DHT, contributes to the development of external male genitalia. During puberty, testosterone also promotes secondary male characteristics such as facial hair, a deeper voice, and increased muscle mass. The other hormones listed do not govern this process: estrogen and progesterone are female hormones, and growth hormone governs general growth rather than sex differentiation.