Aromatase inhibitors are a new family of drugs that have been tried with success in breast cancer therapy and in other hormone-dependent conditions. They are currently investigated for induction of ovulation, as they proved to be effective and not to have the side effects of other currently available drugs, such as multiple gestation and ovarian hyperstimulation syndrome. They have also been tried with success in the treatment of endometriosis, a condition known to be strongly associated with infertility.