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Women have lower metabolic rates than men, likely leading to less oxidative damage to cells. Oxidative damage results from free radicals, which alter DNA, RNA, and protein in cells. This may explain why oxidative damage is linked to diseases such as cancer, Alzheimer's, and atherosclerosis. In animal studies, lowering metabolism by decreasing calorie consumption has been shown to significantly increase lifespan. In addition, because they menstruate, women have less iron in their blood. (High levels of blood iron are associated with oxidation of LDL cholesterol, which contributes to cardiovascular disease.)

Women also enjoy a genetic advantage because they have two copies of the X chromosome. Mutations in genes on the X chromosome typically do not cause disease in females because there is a normal copy. Two X-linked diseases are hemophilia and muscular dystrophy.