Ultrasonography and Sex Ratios in China

This paper directly measures the causal effects of sex-selective abortions on the sex ratio at birth by exploiting the exogenous county-level variation in the availability of B-ultrasound machines. Using data from the 1990 Census of Fujian Province and local records on the introduction time of B-ultrasound machines, we find that the availability of B-ultrasound machines increases the sex ratio at birth by 0.025 in rural areas and 0.117 in urban areas. The rise of sex ratio is especially significant for second births in rural areas when the first birth is a girl