|In recent years, the kindergarten has been getting more and more boys.
Since the late 1970s Chinese couples have been allowed just one child - and most parents here prefer to have a son.
China is worried about what may happen in 20 years or so when these kids grow up and start trying to settle down.
An official estimate says that, by 2020, there may be 30 million men of marriageable age who will not be able to find a wife.
The gender imbalance has various causes. Abortions on female foetuses are believed to be widespread as couples, particularly in rural areas, hope for a son who will look after them in their old age. There is also suspected under-reporting of female births.
On China's tropical island of Hainan, you get an idea of the problems the country might face in a bachelor-heavy future.
In a small village, made up of shacks and pig pens, there are already too many men, and not enough women.
Liu Yaxiao introduces his three brothers - all in their 30s, all unmarried.
They were born before the one child policy began - but they still cannot find anyone to marry.
All the single women left their village long ago in search of work.
At home they have to cook for themselves. That is embarrassing in a country where women are expected to make the food.
The brothers eat lunch by themselves.
They keep an eye on the main road - in case any eligible women wander by. But the road is empty.
In years to come, for the single men of China, things will only get worse.
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