"Actually we are reluctant to adopt in this way. Aside from the huge amount of money, the legal risks are also very high," said Mrs. Li. "I'm afraid I may lose both the baby and money in the end."

Mrs Li and her husband have waited for years to adopt a child left orphaned in the 8.0-magnitude earthquake that struck Wenchuan County of southwest China's Sichuan Province on May 12, 2008.

"The local civil affairs department said the earthquake left 630 orphans, but we waited for five years in vain," said Mr Li. He said he is confident that he can offer an orphan a life better than the average child in China. Both Li and his wife are while collar workers with decent pay.But he has grown impatient in the endless waiting.

Statistics released by the China Population Association at the end of last year show that 12.5 percent of people of childbearing age, or 40 million people, suffer from infertility. Among them, many live in despair.

"I went to the children's welfare institute many times, but came back disappointed every time," said a woman living in the eastern Chinese city of Hangzhou who refused to be named.

She said she was not courageous enough to adopt an unhealthy child.

Sun Jing, an employee at Hangzhou Children's Welfare Institute, said that 99 percent of the children at the institute have disabilities or suffer from chronic diseases, which is the major reason they have not been placed for adoption.

"Many couples come with hope, but few leave with a child," said Sun.

The country's law has strict standards both on children who are allowed to be placed for adoption, and for prospective adoptive parents.

"If a couple goes against the country's family planning policy to have a second child, the child is not legally allowed to be adopted," said Chen Xiaode, who is in charge of children's welfare and charity causes at the Zhejiang Civil Affairs Bureau.

Chen added that couples should not have biological children of their own if they want to adopt.

"People resort to online adoption because the legal procedure is too difficult to go through," said Chen.

Mrs Li and her husband had posted their wish for adopting a baby girl on the website tz667.com. The website, its Chinese name meaning "Home where dreams come true," has become a must-go place for adoptive families and prospective birth parents since its launch in 2007.

According to the website's "About us" page, the non-governmental organization had succeeded in matching 789,203 babies with adoptive parents by the end of 2011.

Lawyers, researchers and government officials however have called for better protection of children's interests and streamlining on online adoption. They also urged to further standardize adoption procedures and deal harshly with activities involving child trafficking.

"Parents sell their healthy babies for good money and send disabled ones to welfare centers. That's why few people adopt children through legal means," said Chen.

Without supervision, online adoption will become a platform for human trafficking, said Jiang Haibin, a lawyer.

Chen suggested the government severely punish those who adopt and give away children privately, as he believes only when people realize there is legal oversight will they stop going to the "black market."

"Adoption is not a business. Only by carrying out strict assessments of both families as stipulated by law does the government know if the adoption is best for the children," said Gao Huajun, deputy head of China Philanthropy Research Institute.