Infertility is the inability to conceive after one year of unprotected intercourse. In women over 35 years old, the diagnosis of infertility is often given after six months of trying to conceive. While the causes of infertility are not always clear, the most common culprits include sperm abnormalities, fallopian tube disease, ovulation disorders and uterine abnormalities. In about 10% of cases, a cause cannot be determined. It is estimated that 15-20% of reproductive-aged couples have difficulty conceiving without assistance. Approximately 85% of couples conceive naturally after one year of trying.