Breast cancer drugs to treat infertility ?

This sounds kind of odd. Why would fertility specialists use a drug intended to treat breast cancer patients to help couples conceive? To those in the field, the concept is nothing new. Clomiphene (Clomid) is a close relative of Tamoxifen, a drug used for years to prevent the recurrence of breast cancer.  These drugs which block the action of the female hormone estrogen, cause hormone fluctuations that stimulate eggs to grow.  Over the past decade, doctors have begun to use another breast cancer drug called Femara or Letrozole to treat couples in with infertility. Like tamoxifen, letrozole is used to prevent recurrence in breast cancer patients, and like clomiphene, it can also be used to stimulate ovulation (release of an egg). Until now, clomid has been the gold standard to help make women ovulate since it is relatively inexpensive and safe. Recently, however, a large study was published suggesting that letrazole may actually be more effective than clomiphene  and result in fewer multiple births. Over time, it is likely that letrazole may replace clomiphene as  a first line fertility drug.