Yes, age is inversely related to fertility. This means your fertility decreases as you age. This is specifically true for women. A woman's fertility peaks in her early twenties, declining gradually by about 30, and steeply after age 35. This comes as a surprise to many modern women who feel young and energetic in their late 30’s and 40’s. The reason for this gradual decrease in fertility is because women are born with a finite egg reserve. With time the egg reserve and quality decreases which reduces your chance of pregnancy. By the time a woman reaches 40 her egg reserves is almost depleted.
Men continue to produce sperm throughout their reproductive lives and generally their fertility is only reduced slightly with age.
If you are planning to postpone having a child for personal or medical reasons, we recommend having your eggs and sperm frozen. It literally freezes your biological clock!