"...an epidemic of loneliness, a distortion of labor markets, and an increase in female trafficking and prostitution."

Carly Cassella reports in science alert,

...Today, in China and India, men outnumber women by 70 million, and it's causing an epidemic of loneliness, a distortion of labor markets, and an increase in female trafficking and prostitution.

...To fix the issue, China has retracted its single-child policy and banned the use of ultrasound machines, which usually tells parents the sex of their child. In India, when parents have daughters but no sons, the government will pay for their child's education and give a lump sump for her dowry or further study - that is, if the parents promise to have no more children.

Tactics like these appear to be working, but while the sex imbalance has somewhat slowed down in recent years, a previous study found the number of missing females is only set to peak in 2050.

Read more here.