Male factor infertility
Fertility is a biological function of both the husband and wife, who, through sexual intercourse, unite their gametes. When a woman has difficulty achieving pregnancy, an evaluation for that problem must involve, not only her, but also her husband. This evaluation can be helpful at giving important information to the couple so they may better understand the future capability of their procreative potential. At the same time, it can be a complex and difficult area to work with.
More here: http://www.naprotechnology.com/maleinfertility.htm