Age can have an effect on male fertility, by affecting the sperm count and the quality of sperm. Although your body decreases some sperm production after age 25, unlike women, you might remain fertile into your 60’s and 70’s. With age you might start to amass problems with your sperm that make it harder for them to fertilize an egg. These can include problems with the shape and movement of your sperm, sperm gene defects, or producing no sperm, or too few sperm.
For women, pregnancy is possible between the time menstruation starts and the menopause finishes. The number of eggs women produce in a lifetime is finite. Women are born with a certain number of eggs that are released every month during ovulation. As women age the body responds less to ovulation inducing hormones and hormones that mature the eggs. The quality of a woman’s eggs and the number released every month decreases from the age of 25, with most women who experience infertility discovering problems after 35.
Age can raise the risk of children being born with genetic defects. With natural conception or pregnancy resulting from IVF treatment, the chance of genetic abnormalities increases in women over 40. The success rate of carrying a pregnancy to term also decreases with age. Women over 35 are at greater risk of miscarriage of ectopic pregnancy.