Human sex ratio

The human sex ratio is the ratio of males to females in a population in the context of anthropology and demography. In humans, the natural sex ratio at birth is slightly biased towards the male sex. It is estimated to be about 1.05 or 1.06 or within a narrow range from 1.03 to 1.06 males per female.

The sex ratio for the entire world population is approximately 101 males to 100 females (2020 est.). The sex ratio of the total population is affected by various factors including natural factors, exposure to pesticides and environmental contaminants, war casualties, effects of war on men, sex-selective abortions, infanticides, aging, gendercide and problems with birth registration.

Human sex ratios, either at birth or in the population as a whole, can be reported in any of four ways: the ratio of males to females, the ratio of females to males, the proportion of males, or the proportion of females. If there are 108,000 males and 100,000 females the ratio of males to females is 1.08 and the proportion of males is 51.9%. Scientific literature often uses the proportion of males. This article uses the ratio of males to females, unless specified otherwise.