Infertility is fairly common. After one year of having unprotected sex, about 15 percent of couples are unable to get pregnant. About a third of the time, infertility can be traced to the woman. In another third of cases, it is because of the man. The rest of the time, it is because of both partners or no cause can be found.
There are treatments that are specifically for men or for women. Some involve both partners. Drugs or surgery are common treatments. Happily, many couples treated for infertility go on to have babies.
NIH: National Institute of Child Health and Human Development