Menstrual Cycle of women.

• You Answered:both women and men

It's true that some men can become new fathers in their 60s or later. But research shows their biological clocks tick, too. Women become less fertile after age 35. The reason: As they get older, they have fewer eggs, and the eggs become less healthy. Fertility changes in men don't happen as suddenly, but age can still affect a man's ability to have sex and the health of his sperm.