We understand gender is a spectrum. We may use gendered terms to talk about anatomy and health risk. Please use this sheet in a way that works best for you and your healthcare provider as you talk about your care.

Older age

Age is a major factor in female fertility. As a woman ages, the quantity and quality of her eggs decline. This becomes apparent by around age 35 and speeds up after age 40. A man makes sperm throughout his life. So age is not as much of a factor. But many problems can affect sperm no matter a man’s age.

Problems with sperm

Health or lifestyle factors can lower the number of sperm (sperm count) in a man’s ejaculate. Even if the sperm count is normal, a man may make sperm that don't work as they should. These may not be able to make the journey through the woman’s reproductive tract. Or they may not be able to fertilize an egg.

Problems with ovulation

Ovulation problems are a common cause of infertility. In some cases, an imbalance of hormones can prevent eggs from maturing. Hormone problems can also stop eggs from being released by the ovaries.

Problems with fertilization

A blockage in the male or female reproductive tract can prevent fertilization. Or sperm may be unable to swim through the cervical mucus. And even if sperm do reach an egg, they may not be able to penetrate the egg’s covering.

Problems with implantation

After fertilization, an embryo may not be able to implant in the uterus. This is often because of problems with the lining of the uterus. It can also result from problems with the size or shape of the uterus.