Over the years, one of the most negative impacts of the One-Child Policy criticized by the international society was an imbalanced sex ratio at birth. There’s no denying that the number of selective abortions and infanticide increased after the policy was launched because the culture favored boys over girls. One of the primary reasons lies in the misreporting of female births according to Gu and Xu (1994). Unwilling to get fined or be forced to have a vasectomy, most families would not register their first female babies, expecting to give birth to a male baby the next time. Some families would place their female babies in a relative’s household and report that the baby passed away. In a word, the imbalanced sex ratio at birth may indicate that there have been a lot of girls unregistered or abandoned in China, not necessarily aborted or killed.

However, after I filtered out countries with a relatively small sex ratio at birth and left countries with larger ones, it can be seen that their numbers all went up at the beginning of the 21st century. The development of fetal ultrasound turned out to be the biggest accelerator of selective abortions among countries that favored boys. Some countries like China and India have legislated against hospitals from revealing the baby’s gender to their parents before birth.