Alcohol consumption during early adolescence may suppress the secretion of specific female reproductive hormones, thereby delaying puberty and adversely affecting the maturation of the reproductive system. These effects occur through several mechanisms, including altered production and secretion by the ovaries of estradiol, a key steroid hormone involved in the timing and regulation of female reproductive events. Alcohol can affect estradiol production by interfering with the normal function of regulatory hormones produced by the brain and the pituitary gland. Recent research has demonstrated additional potential mechanisms for alcohol's effects on female reproductive capability, including interference with specific regulatory systems located entirely within the ovary. Such "intraovarian" systems include the insulin-like growth factor-1 (IGF-1) and nitric oxide (NO) systems. Alcohol can dampen the stimulatory effects of the ovarian IGF-1 system and can increase the inhibitory effects of the ovarian NO system. These effects combine to decrease estradiol secretion. Thus, alcohol impairs ovarian function not only by interfering with hormonal communication between the brain, pituitary gland, and ovaries but also by directly altering the function of regulatory systems within the ovaries themselves. These results provide further evidence of the risks of underage drinking and the importance of its prevention.