Penalties for violators are harsh. Those caught must pay a "social compensation fee," which can be four to nine times a family's annual income, depending on the province and the whim of the local family planning bureau. Parents with government jobs can also lose their posts or get demoted, and their "out of plan" children are denied education and health benefits.
Those without government posts have less to worry about. If they can afford the steep fee and don't mind losing benefits, there's little to stop them from having another child. There's popular anger over this favoring of the wealthy but not much that ordinary people can do about it, since the policy is set behind closed doors by the communist leadership in Beijing.
In 2007, officials in coastal Zhejiang province threatened to start naming and shaming well-off families who had extra kids, but the campaign never got off the ground, possibly because it threatened to tarnish the reputations of too many well-connected people.
Hardest hit by the rules are urban middle class parents with Communist Party posts, teaching positions or jobs at state-run industries.
Li Yongan was ordered to pay 240,000 yuan ($37,500) after his son was born in 2007 as he already had a 13-year-old daughter. After refusing to pay the fee, Li was denied a household registration permit for his son, forcing him to pay three times more for kindergarten.
He was also barred from his job teaching physics at a state-run university in Beijing. "I never regret my second child, but I have been living with depression and anger for years," said Li, who struggles to make ends meet as a freelance chess teacher.
Of course, there are surreptitious, though not foolproof, ways to evade punishment: paying a bribe or falsifying documents so that, for instance, a second child is registered as the twin of an older sibling. Or, sometimes second babies are registered to childless relatives or rural families that are allowed to have a second child but haven't done so.
Wu, the woman who made the early morning escape, said she never intended to flout the one-child rule. She had resorted to fertility treatments to conceive her first child — a daughter nicknamed Le Le, or Happy — so she was stunned when a doctor told her she was expecting again in August, 2008.
The news triggered a monthlong "cold war" with her husband, Wu said. Silent dinners, cold shoulders. She wanted to keep the baby. He didn't. After a few weeks, he came around, she explained with a satisfied smile.
But family planning officials insisted on an abortion. The principal at her school also pressured her to end the pregnancy.
Desperate, she went online for answers — and was led astray.
At her home on the outskirts of Zhuji, a textile hub a few hours south of Shanghai, the energetic former high school teacher recounted how she divorced her husband, then married her cousin the next day, all in an attempt to evade the rules.
The soap-opera-like subterfuge was meant to take advantage of a loophole that allows divorced parents to have a second child if their new spouse is a first-time parent.
Wu had helped raise her cousin, who is 25 and 10 years younger than her, and when she asked if he would marry her to help save the baby, he agreed.
The divorce, on Sept. 27, 2008 involved signing a document and posing for a photo. It was over in just a few minutes. The next day's marriage was similarly swift.
"I remember I was very happy that day," Wu said holding the marriage certificate with a glued-on snapshot of the cousins. "Because I thought I'd figured out a way to save my baby."
But her problem wasn't over. When the newlyweds applied for a birth permit, officials informed them conception had to take place after marriage. They were told to abort the baby, then try again. Wu was back to square one.
A popular option that was out of reach for Wu economically is to have the baby elsewhere, where the limits don't apply. Some better-off Chinese go to Hong Kong, where private agencies charge mainland mothers hundreds of thousands of yuan (tens of thousands of dollars) for transport, lodging, and medical costs.
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