I will never forget the pain I felt 15 years ago when I read a father's book in memory of one of my classmates, who died suddenly of respiratory failure at the age of 18.

The boy was my middle school classmate in Jinan, Shandong province. While my other classmates and I get older year by year, he stays forever 18 years old in our memories - and in the memories of his parents, who have kept their son's room exactly the way it was when he was alive.

It is estimated millions of people in China have lost their only child early. They followed the government's family planning policy when they were young, and most are too old to have another child even though they are allowed to. An immature adoption system and a poor compensation from the government pushes many of them to the brink of collapse.