 Men with infertility and normal hormone levels have few options for fertility treatment. Previous research suggests that men with infertility may have low levels of the active form of Vitamin A, called retinoic acid, in their testes. In a pilot study of 20 men with low numbers of sperm 10 million motile sperm, roughly half the men showed improvement in sperm production. Thus, we want to see if retinoic acid administration to men with azoospermia no sperm present can initiate sperm production. 