The Zhejiang Human Sperm Bank in Hangzhou will offer a maximum bonus of 6,000 yuan ($975) to sperm donors, according to a post on its official micro blog on Sina Weibo, Twitter's counterpart in China, which has stirred hot debate online since May 6.

The sperm bank said its sperm store is at an emergency level again and is offering volunteers up to 6,000 yuan for sperm donations. The number of sperm donors is almost half what it was two years ago, and only 20 to 30 percent of the donated sperm qualified, according to Zhang Junrong, a physician-in-charge at the sperm bank.