More than 24 million Chinese men of marrying age could find themselves without spouses by 2020, says the Chinese Academy of Social Sciences.
"The gender imbalance among newborns is the most serious demographic problem for the country's population of 1.3 billion, says the academy.
It cites sex-specific abortions as a major factor, due to China's traditional bias towards male children.
The academy says gender selection abortions are "extremely common".
This is especially true in rural areas, and ultra-sound scans, first introduced in the late 1980s, have increased the practice.
The latest figures show that for every 100 girls born in China, 119 boys are born, the academy says in a new book.
A reluctance among young urban Chinese to have a first or second child is exacerbating the problem.
In some provinces, 130 boys are born for each 100 girls.
The growing imbalance means that forced prostitution and human trafficking has become "rampant" in some parts of the country."
Russia has a similar problem. It's pretty f-ing sad, if you ask me.