Foremost, China’s rapidly aging population. People weren’t having enough kids, so the population as a whole was aging a lot faster than a vibrant economy’s population should. By 2050, Western and Chinese demographers predicted China will have 349 million people older than 65—more than the entire U.S. population. The sheer size of the aging population looks poised to be a serious drag on the country’s productivity.

But according to new surveys that contradict earlier rosy reports, the ending of China’s restrictions on child-bearing doesn’t appear to be reversing the trend.

New reports suggest birth rates barely budged last year in major provinces like Jiangxi and Shaanxi. Even more concerning, birth rates in China’s poorest regions in the far west actually fell in 2016, as incomes in those regions ticked upward, offering evidence that, similar to their Western counterparts, families are having fewer as they get a little richer.

What’s more, earlier reports suggesting that 2016 had seen a mini-baby boom may have had more to do with fleeting cultural forces, rather than a genuine behavioral shift.

In January, the National Health and Family Planning Commission agency said 18.5 million babies were born last year, the highest number since 2000. That was a nearly 12% increase from 2015, a year hampered by the still-in-effect one-child policy and a weak Chinese zodiac sign (the sheep) that encouraged some parents to hold off on trying to conceive.

Almost half of those new babies in 2016 were second children, which officials at the family planning commission—long known as the abortion police, for their harsh methods to control birth rates—said proved the efficacy of the one-child policy change.

Instead, as the new data suggests, it most likely proved a temporary birth spike.

A spike was natural. Some couples were waiting for the government change so they could avoid being fined for having a second child. Many more were waiting until 2016 so their child could be born in the auspicious year of the monkey, according to the Chinese zodiac calendar.

The maternity wards at hospitals in Beijing and elsewhere said demand had increased by at least 50% in late 2016 compared to the year before—but nurses say it was the the auspicious zodiac sign, rather than a policy change, that couples most often said drove their decision, if anything.

China’s slowing birth rates are rapidly becoming an urgent issue—no longer solely in the purview of demographers and academics. A rapidly aging population will hamper the country for decades to come, unless the government can engineer a miracle that so far has eluded it.