On an average, the lifespan is around 5 years greater for women than men in the United States, and 7 years longer worldwide. The composition of people aged 65 years and older is 57% female, and for 85+ it is 67% female.

Why does the ratio of men and women begin to tilt favorably towards women over time when the ratio is roughly equal in early adulthood?

Major reasons include: 1) Judgment and consideration of consequences of actions are controlled by frontal lobe of the brain, which develops faster in women than men, contributing to fear of death due to violent events and adverse lifestyle decisions. 2) Men tend to have riskier occupations like the army, construction etc. 3) 50% increased likelihood of heart disease related death in men, partly due to lower estrogen levels, and propensity to inadequately controlled blood pressure and cholesterol levels 4) Men are larger than women; across all specimen, all larger species tend to die younger. 5) Men are more likely to commit suicide despite women making more nonfatal suicide attempts. 6) Men tend to be less socially connected than women. 7) Men avoid doctors and health screening more regularly than women.

Early on in life, Y chromosome develops mutations more often than X chromosomes in men. Given the lack of a counterpart X chromosome in men, the X-linked abnormalities are not countered by an alternative normal version. Womb survival rates are also less reliable in male fetuses, as are developmental disorders.

All of this evidence possibly explains why longevity in men tends to be lower than female counterparts. As a fact of science, given the behavioral propensities listed, men should take note and change their behavior components to enhance longevity.