PAPP101 - S03: How demographers think about populations: age and sex

Sex ratios (cont.)

The age pattern of sex ratios

Although at birth the number of males is higher than females, over the course of the life span this reverses. At the oldest ages there may be as few as twenty men for every 100 women. This is due to higher mortality rates for men at every age.

World sex ratio by 5-year age group, 2010.

Source: UN Population Division

This sex differential in mortality rates is largely due to men having riskier lifestyles i.e. men are more likely to smoke, drink alcohol in large quantities, have diets richer in saturated fat, use illegal drugs and be involved in violent altercations. The declining sex ratio due to these tendencies may be exacerbated by the outbreak of war or civil conflict, as it is young men who are at the greatest risk of dying (and possibly in large numbers) at these times.