"When friends ask about my son, I say he's studying abroad and change the subject," a man nicknamed Ordinary Guy wrote on a Chinese forum for grieving parents. "Nowadays I avoid everyone I used to know. I decline my friends' children's wedding invites, and I come to websites like this to find others who understand my suffering."

"When I buried [my daughter] Di-er," a woman said to China's Phoenix TV, "I buried my motherhood along with her."

Among Chinese parents too old to have more children, there's a special grief to losing an only son or daughter. They're called shidu — "those who've lost their only" — and the Chinese media hesitates less and less to call them victims of 1979's one-child policy, which was designed to stall a population explosion, but whose cultural consequences are just now becoming clear. Sina News reports that 760,000 families lose their only child every year.

Compounding heartache is the fact that the state mandates a retirement age of 60 for men and 55 for women. In China's gargantuan social system, single children are often their parents' lone source of companionship and economic support.

Only when 80 bereft parents marched to Beijing's Family Planning Commission in 2012 did this group begin to receive national attention in China — and with it, official haste in increasing their pensions and prioritizing them on adoption wait lists. Chinese reports of graduate student Lu Lingzi's death at the Boston Marathon bombings (as well as other Chinese student casualties in recent weeks) focus heavily on their only-child status. Shidu grief also colors the public outrage over the shoddy school constructions that left hundreds of children dead in the 2008 Wenchuan earthquake. When an only child dies in China, millions of other families sympathize.