Students should be able to describe the roles of hormones in human reproduction, including the menstrual cycle. • During puberty reproductive hormones cause secondary sex characteristics to develop. • Oestrogen is the main female reproductive hormone produced in the ovary. At puberty eggs begin to mature and one is released approximately every 28 days. This is called ovulation. • Testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production. • Several hormones are involved in the menstrual cycle of a woman. Follicle stimulating hormone (FSH) causes maturation of an egg in the ovary. Luteinising hormone (LH) stimulates the release of the egg. Oestrogen and progesterone are involved in maintaining the uterus lining.