Preference for sons, family size, and sex ratio: an empirical study in Korea.

This study investigates the effects of son preference on sex ratio and fertility at the family level, utilizing World Fertility Survey data for Korea, whose population is known to have a strong preference for sons and a fairly high level of contraceptive use. The sex ratio (number of males per 100 females) of siblings in small families is considerably higher than in large families. The sex ratio of last-born children in families of any size is markedly higher than that of the previous children. The sex distribution of children for a given family size, if less than five, deviates significantly from the Bernoulli sequence. The observed frequency of all-girl families is especially small in comparison with the expected value. The sex of the last child strongly influences couples' decision making regarding additional births in all steps of family building except for bearing a second child. In increasing their families to moderate size, parents appear to take into consideration the sex distribution of all earlier births.