Numerous studies have identified specific areas in which the effects of maternal smoking during pregnancy may occur including fetal growth retardation, neonatal deaths, pregnancy complications leading to premature delivery and possible effects on lactation and long-term effects on surviving children. Despite the number of papers which have been published on this subject there is still no clear understanding of the extent to which smoking in general, and various components of cigarette smoke in particular, exert a detrimental effect on the human reproductive potential. Although epidemiological evidence is scanty there are indications that cigarette smoking decreases fertility in women, increases the frequency of menstrual abnormalities and decreases the age of spontaneous menopause. Cigarette smoking in males has also been implicated as a cause of decreased sperm numbers and an increased frequency of abnormal sperm morphology as well as a decrease in sexual performance. Experimental evidence from humans and rodents suggests that nicotine can alter the hypothalamic-pituitary axis through its stimulation of growth hormone, cortisol, vasopressin and oxytocin release which in turn inhibit luteinizing hormone and prolactin release.