In nearly all populations, in the absence of special circumstances, the numbers of males and females are approximately equal; female advantage in life expectancy balances the slightly higher birth rate of boys. Cultural practices such as infanticide, differential feeding, and provision of health care by sex have, in some populations in the past, led to an unequal ratio of boys to girls and higher mortality and morbidity for girls compared to boys. The last two decades of the twentieth century have, however, seen a rapid convergence in the treatment of children by sex, particularly in the developed world. Despite improvements in the treatment of girls and women, inequalities still exist, most notably in developing countries in Asia and Africa.