China is facing a demographic crisis. It is heading towards becoming a nation of bachelors, with official statistics predicting as many as 40m single men by 2020.
The shortage of women is due to a traditional preference for sons, combined with the effects of China's strict birth control policies.
On Hainan Island, which has the worst gender imbalance in the country, A Jun dangles her baby girl on her hip as she waddles towards the village well. At 22, she is heavily pregnant with her second baby, and there is pressure on her to have a boy this time.
"My husband wants a boy," she said. "If the second child's a girl, I'll have another. I want to have a boy too."
So great is her desire for a boy, she is willing to risk a fine and the wrath of the government to have a forbidden third child. She lives in Pingling village, deep in the tropical hillside of Hainan island.
It is a poverty-stricken collection of stone houses which depends on a few small plots of land to scratch out a living. With social security systems non-existent in places like this, families count on sons to look after them in their old age.
"In this sort of village, they treasure boys and don't care about girls," A Jun's friend, Hua, explained.
A Jun says she hopes to have a boy this time
"People think sons will look after them when they get old. But once girls get married, they belong to someone else. They're not part of your family any more."
Starting in 1980, the Chinese government limited each family to one child to try to avert a population explosion. But popular discontent in rural areas led to a policy change in 1984, according to population expert Zhai Zhenwu from People's University in Beijing.
"In most of the countryside in China we have what we call one-and-a-half-child policy. That means if a young couple's first child is a male, they must stop child-bearing. If the child is a female they may have a second child," he said.
That - and premature female infant deaths - has led to a glut of baby boys. And Hainan island has the highest boy-to-girl ratio in the whole country, with 135 boys born for every 100 girls.
According to Zhai Zhenwu, people in Hainan still have a very traditional outlook as development there has lagged behind the mainland.
"Social and economic development in Hainan is lower than other provinces on the mainland. The government didn't want to develop Hainan because it is in the frontline of Taiwan, so the government didn't invest much there."
He said the startling gender imbalance did not emerge until the late 1980s when ultrasound machines became common and expectant parents could find out the gender of their child.
Many men from Pingling cannot find wives
"People always want to know whether they're having a girl or a boy," said ultrasound technician Chen De, who works in the maternity hospital in the small town of Wenchang.
"They often offer me money to tell them."
He is forbidden to do so by law. But he said some people were willing to break the law.
"Until a few years ago, private clinics had ultrasound machines and would tell you the gender of your child. Now they're strictly controlled as the government has clamped down. But many of the ultrasound machines are now in illegal clinics, so people still have ultrasounds done in secret."
Baby girls are often aborted to give parents another chance at having a boy. It is illegal, but that does not make any difference.
"I wanted a boy, and it was the only way," one man said, admitting he had encouraged his wife to abort a baby girl. And mortality rates for female infants are much higher in Hainan. One paediatrician, who did not want to be named, gave a chilling insight into why.
"If a baby boy gets sick," she said, "Its parents will sell everything they own to save their son's life. If it's a girl, very often the parents don't have such a positive attitude. Sometimes they just stop the treatment and take the baby home."
She estimates that 70% of the newborns in her hospital are male. And statistics indicate that as many as two million extra boys are born every year nationwide. These are men who will not find wives, and Chinese officials have warned that this gender imbalance could lead to an increase in prostitution, sex crimes and wife-buying.
As the first generation of children born under the one-child policy is only just reaching marriage age, the problem of surplus men is not yet a major one nationally.
Xiao Ming says he cannot find a girlfriend
But in some places it is starting to emerge.
And Pingling is, in this sad way, ahead of its time. Many men in the village cannot find wives. It is not because of the gender imbalance but because a huge flood washed away the villages' fertile soil, so it is poorer than its neighbours.
But in a country where marriage is the norm, Pingling's status as a bachelor village is a source of great shame.
"I don't have a girlfriend, I can't find one," said 25-year-old Xiao Ming, blushing furiously, as he concentrates on chopping bamboo. "It's because I can't speak properly and I don't understand romance."
One old man in the village, Qiao Liangguo, has four sons - three of them cannot find wives. As he recounts his misfortune, his eyes water and he rubs a weary hand over his wrinkled forehead.
"Now in our village, we have no water, no rice and no money. Wives aren't easy to find. My fate is bad. No one wants to marry my sons."
As dusk falls, the young men of Pingling play volleyball. The happy sounds mask the absence of women and the villages' faltering future.
An environmental disaster has damaged this village - but the social cost of China's gender imbalance will be man-made.