Followings are the function of testosterone:
1. In males, testosterone directly increases size and mass of the muscles, bones, vocal cord.
2. It stimulates the growth of body hairs including abdominal, chest and pubic hair.
3. Enlargement of the larynx (Adam's apple) and deepening of the voice.
4. Broadening of shoulders and chest.
5. It helps in formation of sex organs in the fetus
6. Helps in growth of spermatogenic tissues in testicles and maintain male fertility.