There are many different causes of infertility in both women and men that may be identified. Some are identified as male factors and others as female factors. In 15% to 20% of cases, no clear causes can be identified.

• Difficulties with ovulation occur in about 25% to 40% of cases and with fallopian tubes in 15% to 20% of cases.
• About 15% to 20% of couples have more than one reason for their infertility.
• Up to 60% of couples who haven't conceived after a year of trying, and who continue to try to get pregnant, will eventually conceive with or without treatment—even in cases when no clear cause of infertility can be identified
• Endometriosis

Significant advances in our understanding of the causes of infertility allow for more effective treatments