Clomifene (Clomid, Serophene, Milophene)

• what "fertility pills" are usually made of
• used to treat female infertility due to anovulation (lack of ovulation)
• doesn't work if infertility is caused by the dude (defective or lack of spermies) or woman's infertility is caused by ovarian dysfunction
• inhibits the negative feedback action of estrogen in the anterior pituitary gland, resulting in increased release of follicle-stimulating hormone (FSH) - this leads to a higher rate of ovulation and hence increased potential for pregnancy
• can actually cause multiple ovulation, increasing the risk of multiple births
  
• sometimes four or five ova are released and fertilized - say hello to the local news crew, quintuplets!
• actually is a mixture of two geometric isomers, enclomifene and zuclomifene
• used (abused?) by some male bodybuilders to block the estrogen-like effects (e.g. man titties!) produced by anabolic steroids and restore the body's natural production of testosterone (which is lost with steroid use)
  

http://en.wikipedia.org/wiki/Clomiphene