A couple is said to be infertile if pregnancy does not result after one year of normal sexual activity without contraceptives.

About 25 percent of couples experience infertility at some point in their lives. The incidence of infertility increases with age. The male partner contributes to about 40 percent of cases of infertility. A combination of factors is common.

Factors to consider, in consultation with your physician:

• Adequate sperm production and semen delivery (impaired for 40 percent of...