One of China's most influential expat writers says the country's one-child policy has had alarming unforeseen consequences and produced a generation of "little emperors" whose values are dangerously skewed.

British-based writer Xinran Xue interviewed some of the 150 million single children who were born under the policy for her latest book, Buy Me The Sky.

She said she was shocked to find just how amoral many of them were.

"That made me hurt because I used to be so proud of being Chinese," she said.

Xinran said the basis for this cultural pride was that Chinese people valued the family.

But now, she said, "our culture beliefs have been betrayed by this".

She said she was afraid because this was the generation that would determine the future of China and its place in the world.

Xinran was shocked by the 2011 murder case involving a pampered music student who protected his hands so he could play the piano and who only carried a knife so that his parents or friends could cut his fruit.

But one evening he was driving his car and knocked down a pedestrian. He stopped his car, but when the bloodied mother asked him to help her, he stabbed her to death.

"He didn't think of the life-endangered women, he first thinks his father will punish him, so he took the fruit knife, which he never touched, used his fingers, which played beautiful piano and stabbed this women to death," she said.

But what rocked Xinran even more was the reaction to the death penalty ultimately imposed against the piano student.

"I was really shocked to find that one group of students from one-child policy, they are all single, and even the girls they say, 'If I were him I would do the same things because our lives are much more valuable than them and we don't want those peasants to give us future trouble'.

"That really shocked me, how much society, or our beliefs of the value of the human life been changed by those single children.

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"And also how less they're being educated how to respect we should be equal between city and the country, rich and the poor."

'Winners' of one-child policy

Xinran's previous book focused on the brutal effect of the one-child policy on mothers who had to hand away their babies and on the baby girls who were adopted out or killed.

Around 30 million fewer girls than boys were born under this policy.

In her latest book Xinran wanted to focus on the winners from the policy — the children who remained with their parents.

She was surprised not only by how pampered they were but how unhappy they were.

"I always think about — not about how those men will find wives — but what about the 30 million missing girls," she said.

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"One by one, where are they all? And the problem is, these winners, most of them have no idea how lucky they are or what's the price that the Chinese family, including their own parents, paid."

Xinran said the values of the children born under the policy had been skewed, yet these children would one day be leaders in their country.

"When they brought into the society about this policy, I don't think they did prepare it very well because the child had no knowledge about family," she said.

"They're very lonely, then they come to school from kindergarten, everybody [is] the same, so no-one [to] talk [to], no brothers, sisters, so they [don't] know how to share.

"I'm quite worried, because your life is [about] how to be with others, finding your love, build up your own family, give your talent to society, have someone you need to have. That is part of your life before this generation."

Struggling to find partners, start a family

One of the stories Xinran shares through her book is of her friend's son Du Zhuang; when he arrived in London to stay with Xinran and her son, they soon discovered he had difficulty with even the simplest tasks.

"When I met him at Heathrow airport he was on the phone and the first second he saw me just passed the phone to me, saying 'My mum wants to talk to you'," she said.

"Then his mum shouted and said: 'Xinran, I give my son to you, make sure you open the suitcase for him'.

"She said: 'He has no idea how to open his suitcase and hang out his own clothes'. I said he just graduated from university, and the mum said: 'Yes, every single weekend I went to his university to tidy up his bedroom'."

Xinran said she hoped the single children would realise the problem when they became parents.

But there is a big question mark over whether this generation will embrace having children of their own.

In 2013, China loosened its one-child policy so single children themselves could have more than one child.

But Xinran said she found some children of the policy were finding it hard to live with a partner, let alone have a child together.

She recounted some brutal responses from teenage single children protesting against their one-child parents now trying for a second child.

"One girl was 13 and she told her mum, 'If you don't stop, I don't want anyone to share my family, I will jump off the building'," she said.

"So the mum had [an] abortion. Then two other families the parents tried to argue with the children, but unfortunately the same thing happened, one [was] 14, [the other was] 18, they did jump off the building.

"Again, back to my basic question: 'How to see the family? What [does] family mean to those single children?'

"And my hope that those single children see who they are — I think they just need time."