Infertility is a condition in which a couple is unable to become pregnant after 1 year of attempting pregnancy by having sex without using birth control.
Common causes of infertility include poorly timed intercourse, and problems with ovulation, sperm production, the fallopian tubes, the uterus, or ejaculation. In some cases, no cause can be found (unexplained infertility).
WebMD Medical Reference from Healthwise