Last week China ended rules limiting families to just one child. But the demise of this troubled 35-year experiment in social engineering is unlikely to spark a baby boom and jumpstart economic growth. Despite what Communist Party leaders may hope, available data suggests that China is now truly a single-child society. Even when given the option to have two kids, many parents will stick to one. The policy, meanwhile, has created a population swollen with tens of million “surplus” men from sex-selective abortions —pregnant women used ultrasound to scan the sex of the fetus and aborted if it was female. (In most parts of the world, data suggest that parents still prefer boys over girls; in China, a major reason is that men carry forward the ancestral line.) That demographic mess will take decades to clean up.

The one-child policy was based on a mid-20th century Western promise: Slashing the birth rate would yield a “demographic dividend” of abundant working-age people with few dependents to support.  People around the world were already living longer than ever before, thanks to advances in public health, and concern about global population growth had reached a feverish pitch. By the early 1970s, when Chinese leaders began instituting policies directed at reducing births, Western aid organizations and governments were backing population control schemes in developing nations throughout Asia. In South Korea in 1965, for example, the U.S. Agency for International Development delivered eleven U.S. Army ambulances, reconditioned as mobile contraceptive clinics for use in rural villages. Poorly trained health workers were paid piecemeal for performing sterilizations and inserting intrauterine devices. In 1972, meanwhile, a group of scientists called the Club of Rome released a controversial report on population size and world resources, called The Limits to Growth, that caught on among China’s elite.

A few years later, Chinese leaders began deliberating tightening their birth directives into a one-child policy, which they formally unveiled in 1980. According to Shanghai Academy of Social Sciences economist Liang Zhongtang, who participated in debates about the policy’s adoption, the findings of The Limits to Growth—though widely criticized elsewhere—swayed some of the decisions in China. Indeed, one influential proponent of the policy, Soviet-trained missile scientist Song Jian, applied theoretical methods borrowed from European mathematicians to generate wild population growth projections for China that helped sway leaders to adopt the birth limit.

Today, 12 percent of China’s population is over age 60, with a paucity of young people to provide economic and social support. China’s working-age adults are unlikely to spark the hoped-for baby boom, because they include tens of millions of men who cannot find women to marry. There are 62 million  “missing” women and girls in China from sex-selective abortion and neglect, according to one recent estimate.

The gender and age imbalance are often portrayed as surprising after-effects of the policy. But they were foreseen from the start. China has a history of female infanticide, and in 1975, medical researchers at Tietung Hospital in Liaoning showed that sex-selective abortion could be another way to achieve the same ends. The scientists wrote in the Chinese Medical Journal that they had successfully determined fetal sex in ninety-three pregnant women using a crude form of a chorionic villus sampling, a procedure that involves taking a biopsy of the thin membrane that separates a fetus from its mother in the womb. Nearly one-third of the women chose to abort after learning they would have girls, the researchers dryly observed. A much larger experiment on abortion and sex selection—this time performed with amniocentesis—was conducted that same year in India, with similar results.

Sex selection, in fact, had been linked with population control since at least the 1950s, when research emerged showing that around the world, couples kept having children until they had a son. Long before ultrasound made sex determination easy, experts at a 1969 workshop convened by the U.S. National Institute of Child Health and Human Development and the American Association for the Advancement of the Sciences identified sex selection as a promising research area for scientists working on population control. When reports that couples squeezed by the one-child policy were aborting female fetuses first trickled out of China in the early 1980s, it could hardly have been a surprise.

As for aging? Before the policy’s adoption, Liang brought up the aging issue, raising the question of who would support the elderly. But others thought that vaguely defined future scientific advances would help China address the problem. And an older population was, to some extent, the whole point. The one-child policy’s architects were not so concerned with the long term.

By 2013, a different government worried about missing youth began to relax the limits.  Couples were allowed to have two children if one parent was an only child. However, the takeup was unenthusiastic, because the priorities of average Chinese citizens had changed over the decades. Many families now live in cities, where the costs of raising children are high.

Even if the policy’s abolition leads to a sudden baby boom—and demographers say it won’t—China’s statistics are still stacked against a rise in the birth rate. With fewer potential mothers after so many abortions of females, there will be fewer children. (This effect was not lost on early population control adherents. At a 1970 Population Association of America meeting, Duke University demographers William Serow and V. Jeffrey Evans demonstrated that an imbalanced sex ratio would lead to a much quicker reduction in births.)

The end of the one-child limit is unlikely to change things anytime soon. In 2010, the last year in which a census was conducted, Chinese had 118 boys for every 100 girls—far above the natural sex ratio of birth of 105 boys per 100 girls. Even if the sex ratio at birth were to normalize tomorrow, Catherine Tucker and Jennifer Van Hook, demographers with Pennsylvania State University’s Population Research Institute, recently calculated that fully 10 percent of working-age men in China would still lack a female counterpart in 2050—and that’s assuming that men start marrying women their own age, a change from their current practice of seeking mates a few years younger. In a society with a stable fertility rate, marrying younger women would help offset the gender imbalance—but China’s birth rate is currently so low there are fewer and fewer young women coming into the marriage market.

The shortage of marriageable women has had other disquieting social implications. There has been a spike in sex trafficking and bride buying. The excess men, uninvolved in family life and less tethered to social institutions, have contributed to government leaders’ fears of instability.

All of this could come to a head in 2030. In that year China is expected to overtake Japan as the world's most aging society, and the number of working-age men without female counterparts will peak at 29 million (and that’s assuming that the sex ratio at birth begins to drop tomorrow). Perhaps by that distant year China’s leaders will have figured out new, respectful ways to value women in society, and can also get the economy back on track.

Mara Hvistendahl is the author of Unnatural Selection, an investigation into the effects of widespread global sex selection that was a finalist for the Pulitzer Prize and Los Angeles Times Book Prize.