Last month, Chinese internet conglomerate Alibaba stepped in to help temporarily relieve China’s sperm shortage: It put out a call for male applicants who, if healthy, would be paid 5,000 yuan ($805) for a donation. In 48 hours, over 22,000 men signed up.

If only it were equally simple for women in China to store their eggs—a hot topic since local media reported on several celebrities who, concerned about their age or the quality of their ova, have had their eggs frozen to allow them to delay motherhood. Of particular concern to Chinese women: The celebrities traveled abroad to escape strict laws on egg freezing; in China, married women face many restrictions on freezing their eggs, and the process is entirely closed to single women.

China’s ban on freezing eggs is officially in place to prevent an illegal ova trade but—unfortunately for many—freezing eggs is also against the interests of the state. In recent years the government has been trying to encourage women to give birth, rather than to put off motherhood, and freezing eggs could act against that.

This is essentially because the government is concerned that there won’t be enough young people to drive GDP growth and take care of the country’s elderly, thanks to the one-child policy and the population bomb it’s created.

A senior official at the Shanxi province family planning bureau—which is responsible for enforcing the one-child policy—even called publicly for a “two-child” policy and for the strong encouragement of all couples to have children. That was met with criticism in China, but the government has been loosening the one-child policy, and it also has soft-power measures with which it can encourage couples to conceive.

Several years ago the phrase shengnv, meaning “a leftover woman,” entered Chinese parlance. It is a derogatory term aimed at unmarried women aged 27 or older. Even the supposedly pro-women All-China Women’s Federation (ACWF) filled its website with articles about the horrors of a woman entering her late 20s without the prospect of starting a family on the horizon. The pressure such stories put on women can’t easily be measured, but it’s very real all the same.

The push for traditional family units, and particularly for the conception of a child, even features in reports directly concerning egg-freezing. An article on the issue by state newswire Xinhua carried advice from China’s family planning bureau that, “Women should get pregnant in their prime child-bearing years, between 24 and 29. Pregnancy at over 35 can be dangerous to both mother and fetus.”

The ACWF also ended its report on the topic with quotes from a gynecology doctor at the respected Fudan University, who detailed the dangers of storing eggs, and added: “I would suggest that healthy women have children rather than store eggs as an ‘insurance policy.'”