BEIJING -- Questions have been raised about the reliability of the latest demographic numbers out of China, with critics accusing the government of manipulating data while some officials scratch their heads over numbers that do not seem to add up.

The National Population Census for 2020, released Tuesday , shows the country had 253.38 million children 14 and younger. Meanwhile, new births between 2006 and 2020 -- the period during which these youngsters were born -- total about 239 million, based on data from the National Bureau of Statistics. This gap of over 5% means slightly more than 14 million children somehow joined the 0-14 age group.

The once-a-decade count was slammed as "the most unreliable census" by Yi Fuxian, a reproductive science researcher at the University of Wisconsin-Madison in the U.S. and a critic of China's population control system.

The survey covers mainland citizens, excluding people in Hong Kong and Macao. The 5% discrepancy would make sense only if some 14 million foreigners became Chinese citizens. But even an official close to the Communist Party shot down the idea, saying it is just "not possible."

At a news conference Tuesday, the statistics bureau denied any data adjustment.

The latest census showed that the population of the 0-14 age group grew 13.8% from the previous survey in 2010. The increase demonstrates that China's 2016 decision to drop its one-child policy and allow couples to have two children "has achieved positive results," the bureau said.

But this claim was met with suspicion. Fewer babies have been born since a 2016 peak. The census showed that China recorded 12 million births in 2020, the lowest in 59 years. The count of newborns also represents a year-on-year decline of 18% -- the steepest since the 1949 revolution that led to the founding of the People's Republic of China.

The Communist Party leadership apparently wants to prove that the new two-child policy is working. Otherwise, it risks facing mounting calls to end its long-running family planning program, particularly now that the country must quickly hammer out steps to address its aging society.

The latest census showed that the workforce is shrinking while the population of the elderly ballooned about 60% between 2010 and 2020.