Sex ratio includes the number of males for each female in five age groups – at birth, under 15 years, 15-64 years, 65 years and over, and the total population. Sex ratio at birth has lately emerged as a symbol of certain kinds of sex differentiation in some countries. For instance, high sex ratios at birth in some Asian countries are now connected to sex-selective abortion and infanticide due to a strong preference for sons. This will affect future marriage patterns and fertility patterns. Ultimately, it could cause unrest among young adult males who are unable to find partners.