For decades China has been a top destination for Americans seeking to adopt a child from abroad, but now its own citizens are making the reverse trek to the US to find surrogate mothers.
After cancer left her unable to bear her own children three years ago, one Chinese woman in her late 30s -- who asked for anonymity -- decided to research her options.
Her eggs were still viable, but her choices were few with surrogacy illegal in China, so she and her husband set their sights abroad, ultimately deciding on the US.
After a trip to Los Angeles last year to transfer their eggs and sperm and an extended visit to their surrogate's home state Tennessee for the birth and subsequent formalities, she and her husband are now the happy parents of three-month-old twins, at a cost of $150,000.
"I wanted to do everything properly," she said by phone from the US. "We have a lot of underground (fertility) therapy agencies in China, but I just don't trust the doctors."
With the cost standing at around 34 times average urban incomes in China it is a process reserved mainly for the rich.
'We get calls every day'
A dozen US-based surrogacy agencies contacted by AFP say they have seen a marked rise in Chinese clients over the past three years.
The Agency for Surrogacy Solutions in Encino, California, recently had its contract translated into Chinese and is working with a Chinese-speaking consultant to recruit potential customers.
"A third of our clients are Chinese," said its president Kathryn Kaycoff-Manos, up from virtually none three years ago. "It's huge. And we get calls every day."
Stuart Bell, the co-owner of Los Angeles-based Growing Generations, one of the world's largest surrogacy agencies, added Beijing and Shanghai to his Asia itinerary for the first time in September, meeting about 10 potential clients in each.
"There seems to be a lot of infertility going on in China," he said, and frustration over the options available.
The Chinese Population Association estimates 40 million people are infertile in the country -- one in eight of the child-bearing population, four times the proportion 20 years ago.
Two-thirds of the semen at Shanghai's main sperm bank failed to meet World Health Organisation standards, the Shanghai Morning Post reported, with experts citing heavy pollution as a main contributing factor.
About 60 to 70 percent of Chinese clients seek surrogacy for medical reasons, US agencies say, but there are other motivations related to Chinese law.
Gay couples looking to have children cannot adopt in China and are increasingly turning to the US, they say, as are government employees sidestepping China's one-child policy.
There are several exceptions to the rule, including multiple births, and the Communist Party has promised to adjust it further. But wealthy Chinese who want more than one offspring are largely able to do so simply by paying a fine, with the average penalty in Beijing estimated at 100,000 yuan ($16,400) according to the official news agency Xinhua.
For government employees the calculation is more complicated, as their jobs are in jeopardy if they are discovered to have had a second child -- so avoiding appearing pregnant is key.
"I once helped a Beijing couple -- their son is almost two years old now, and the intended mother worked for a state-owned bank," said one China-based surrogacy agent.
"As general manager in a leading position, how could you violate the policy yourself?"
Other motives include older professional women who put off having children for the sake of their careers.
On his last trip, Bell said, he met a married woman in her mid-40s who worked her way up to a top job at a large financial firm but felt she lost track of her priorities along the way.
"'I worked so hard to get where I am, only to get to the point where I forgot the most important thing'," he quoted her as saying.
'We don't have any regrets in life'
California is the destination of choice for most Chinese couples because of its well-established surrogacy industry and welcoming legal framework, noted Andrew Vorzimer, a Los Angeles-based attorney who called its reproductive law regime "the best in the world".
The Golden State generally allows both client parents to be named on the birth certificate, excluding the surrogate and enabling the child to be recognised as theirs under Chinese law.
"Commercial surrogacy, really the birthplace was California," said Vorzimer.
After Tony Jiang, 36, of Shanghai, and his wife had three children through a Californian surrogate they had so many inquiries he left his job to start his own fertility consultancy.
"I think if we go abroad, we try to do it in the best place we can find in the world, because after trying it there, we don't have any regrets in life," he said.
There are some fringe benefits to pursuing surrogacy in the US, including the child having American citizenship and an increased likelihood of twins or triplets through in-vitro fertilisation.
But Jiang insisted: "It's not a kind of fashion. It's only for people in true need."
The process is long and convoluted, and Chinese clients risk stigmatisation if the truth emerges.
"Especially for some Chinese, they don't much discuss this openly," said the new mother. "Even if they have children through therapy in the US, when they bring them back home, they won't mention about the therapy at all.
"They don't want people to know."