A Chinese mother rests with her daughter while shopping at a furniture store in Beijing, Jan. 19, 2015. Getty Images

For years, having a second child in China cost parents thousands of dollars in fines and a lot of anguish. If they didn't pay, officials often wouldn't register the kids, preventing them from legally accessing school, medical care and ID card services. But now that the government has ended the country's long-held one-child policy, moms and dads are fighting back.

Parents gathered outside state family planning offices in Beijing Tuesday to protest social compensation fees previously associated with having a second baby, the Associated Press reported. They held signs that read, "They are all our motherland’s flowers and should not be treated differently."

China's ruling Communist Party announced in October it planned to lift a 35-year-old policy limiting most couples to one child in an effort to limit population growth. Just before the new year, authorities announced they were also abandoning the high social maintenance fees associated with having second children. The updated Population and Family Planning Law went into effect Friday, the Business Standard reported.

But that wasn't enough for parents like Wan Changru. She and about 20 other family members want the government to cancel their unpaid fines for having multiple children before the new rule. About 14 million people in China were found to be unregistered in the nation's 2010 Census, according to the Associated Press.

Wan made headlines in December when she and her husband filed a lawsuit to register their daughter without ponying up the 45,677 yuan ($7,000) fee. "I simply cannot afford to pay such a large sum of money," Wan told AP at the time.

Attorney and advocate Wu Youshui told the Christian Science Monitor recently that he estimated the fines generated about $8 billion a year for the government. But he said no authorities would say exactly what they were being used for.

It's "legally unreasonable and morally wrong," the lawyer said. “It is inhumane, but officials do it because it makes it easier for them to raise money.”