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

• 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.

Male factors contribute to about 30% to 40% of all cases of infertility and thus are an important part of the infertility evaluation.

To be considered fertile the male partner must be able to deliver an adequate quantity of healthy sperm to a woman's vagina during intercourse. Many things can interfere with this process, several of which relate to variations in sperm quality or an absence of sperm. Other factors include varicocele abnormality, retrograde ejaculation, and lifestyle factors.

Assessment for male factor infertility starts with semen analysis