Follicle-stimulating hormone, or FSH, plays a role in the proper functioning of the reproductive systems of men and women. According to WebMD, it works in the female body to "help control the menstrual cycle and the production of eggs." In men, it helps to control sperm production.
While the amount of FSH in the female body fluctuates at different times in the menstrual cycle, the amount in the male body stays the same. FSH is at its highest level in a woman just prior to ovulation. The pituitary gland produces this hormone. Abnormal levels in either a male or female are a potential cause of fertility problems.