Many couples who want a child face the problem of infertility-they have tried to conceive but have not been able to do so. Couples are considered infertile if they have not been able to conceive after 12 months of having sex without the use of any form of birth control. About 14% of couples in the United States are infertile. Infertility may be due to many problems. More than one factor may be causing the infertility. Some causes are easily diagnosed and treated, while others are not. In come cases, no cause can be found in either partner. If you and your partner are infertile and you want to have a child, you should think about having an infertility evaluation. This is done by your physician to find out what is causing the infertility and what can be done to correct it.