PIP: A tentative yet comprehensive review of the effects of smoking on reproductive capacity includes conception, sperm morphology, teratogeny and intrauterine growth retardation, cancer, timing of menopause, estrogen secretion, in vitro fertilization and estrogen metabolism. Smokers are estimated to take 3.4 times as long as non-smokers to conceive, and are reported to be less fertile. Spermatozoa are both abnormal morphologically and genetically compromised, in proportion to dose. Smokers have greater viremia in mumps and can get mumps orchitis. Smoking is said to cause impotence. Smoking increases risk of spontaneous abortion, intrauterine growth retardation and congenital abnormalities, in proportion to dose, starting with sidestream smoke. Smoke is directly toxic to the ova, and indirectly deleterious because it decreases estrogen secretion. Women smokers tend to the thinner, with lower estrogen levels, a factor in their lower success rates with in vitro fertilization. Smoking may speed up metabolic degradation of estrogen via the 2-hydroxylation pathway as well. Finally, smokers have earlier menopause, with accompanying osteoporosis and fractures.