"IT feels weird to know that someone you meet on the street someday could be your child," said "Zhou Zheng," a sperm donor from north China's Hebei Province, who has complicated feelings about the donation he made a decade ago.
Zhou was in college when he decided to donate his sperm out of compassion for the reproductively-challenged couples. But the thought of being the biological father of a child he doesn't know scared him away from ever doing it again.
As per Chinese law, sperm donated by one person can be used to impregnate up to five women. This means that Zhou, who is married with his own child, could actually have as many as six offspring!
"Knowing I might have five other kids out there really freaks me out," he said.
Sperm banks are dealing with a worsening shortage of healthy sperm, despite repeated efforts to recruit more donors.
Almost three decades after China opened its first sperm bank in central China's Hunan Province, the Hebei Human Sperm Bank has become the latest fertility institution in China to report a shortage of qualified sperm.
According to the sperm bank's director Zhao Bangrong, there are currently 700 couples waiting for sperm, but the bank only had 200 donors in the first six months of this year, compared with 650 volunteers during the same period of last year.
Not all volunteers can donate. Only 20 percent can meet the requirements set by health authorities to ensure their sperm is of the highest quality.
People with hereditary diseases or who have been exposed to radioactivity, as well as those with a history of heavy smoking or drinking, are not permitted to donate. There are also requirements for active sperm counts in semen samples.
"People incorrectly assume that being disqualified for donation means you have reproductive problems," Zhao said.
Another factor is cultural perceptions. Some balk at donating because they believe it amounts to a betrayal of one's ancestral bloodline, which, according to traditional beliefs, should be preserved within one's family. "In China, sperm is traditionally considered a prized part of the human body. Many people fear that giving it away could be harmful to their health," Zhao said.
Statistics released by the China Population Association at the end of 2012 showed 40 million people have fertility issues, accounting for 12.5 percent of the population aged between 20 and 49. The ratio increased from 3 percent two decades ago.