BEIJING — A boy delivered in a Beijing maternity ward yesterday became China's 1.3 billionth citizen, the government said, using the occasion to tout its controversial one-child policy.

China imposed a policy of allowing one child a family about 30 years ago, after a post-World War II baby boom. Couples who have unsanctioned children have been subject to heavy fines, job losses and forced sterilization.

China would have reached 1.3 billion citizens four years earlier if it weren't for its family-planning policy, according to the official Xinhua News Agency.

The government says that without the policy, China would have at least 200 million more mouths to feed, straining its resources.

Foreign experts say China's true population could be hundreds of millions above 1.3 billion because many rural families have unreported children. The one-child limit also is frequently ignored by urban couples who can afford the fines or are desperate for a son to carry on the family name and care for them in old age.

The boy was born at the Beijing Maternity Hospital at 12:02 a.m. to a father who works for Air China and a mother employed by Shell China, Xinhua said.

Government spokesmen deny that women are coerced into having abortions, saying forced abortions aren't sanctioned and officials who carry them out can be punished.

The U.S. government is among those who say forced abortions occur, and it has withheld money from the U.N. Population Fund the past three years because the agency supports the Beijing government's family-planning program.

In Washington last month, State Department officials testified to Congress that China's program is abusive.

They cited the case of Mao Hengfeng, a Shanghai woman serving 1-1/2 years in a labor camp for her campaign to abolish coerced abortions. Since her second pregnancy in the late 1980s, Mao has been detained in psychiatric wards, forced to have an abortion and removed from her job.

On Wednesday, the New York group Human Rights in China said her sentence had been extended by three months.

In an unusual acknowledgment, the China Daily said yesterday, without providing specifics, that the "family-planning policy has gone awry in some places during its 25-year history." However, it said, "The policy should continue to be endorsed."

In China's business capital, Shanghai, where city leaders worry a low birthrate will cause a shortage of workers, divorced residents who remarry are allowed to have a child with new spouses, even if they have a child from a previous marriage.

China says the birth limits have reduced the number of children per couple from about 5.8 children in the 1970s to 1.8 children now.

That success has brought "a string of demographic challenges," Xinhua said in a separate report yesterday.

Fewer children will result in a smaller pool of young workers to support a large population of retirees, it said. There is also a widening gap between the numbers of boys and girls, leading to fears of social strains as millions of men in coming years are unable to find wives. Government figures say 119 boys are born in China for every 100 girls, a gap blamed largely on parents aborting female fetuses so they can try again for a boy. Officials say China could have as many as 40 million men who can't find spouses by 2020.