What are the 4 secondary sex characteristics that develop in males during puberty?

1. Enlargement of the testes and penis. The testes produce sperm and testosterone, the hormone responsible for the development of male secondary sex characteristics. Testosterone also causes the penis to grow longer and thicker.

2. Growth of pubic hair. Pubic hair begins to grow around the base of the penis and spreads to the pubic area.

3. Deepening of the voice. The vocal cords thicken and lengthen, resulting in a deeper voice.

4. Increased muscle mass. Testosterone promotes the growth of muscle mass and strength.