The Chinese government continues to insist that its “one-child” policy, which was on the books from 1979 to 2015, was a success, and in purely numeral terms it was. As this documentary by Nanfu Wang and Jialing Zhang notes, it did “solve” a perceived problem of overpopulation due to a birth rate that, it was believed, threatened the country’s socio-economic future by preventing an estimated 300,000-400,000 births.

But the film also shows that the consequences were horrifying, in terms of brutal enforcement and the emotional devastation it inflicted. “One Child Nation” is a sobering indictment of the harm a government can do to its people when it attempts to engineer social policy.

Wang, who co-directed the film with Zhang as well as shooting it in collaboration with Yuanchen Liu and then editing the footage to its present eighty-five minute running-time, was born to a village family while the policy was in force, but her parents received an exemption: they could have a second child, but only with a five-year interval between the two. When her younger brother was born, he became the apple of their parents’ eyes, chosen to continue school while Wang was sent to work. She later emigrated to the United States and became a mother herself, inspiring her to undertake this, her first film, from a sense of personal need.

In a way Wang was fortunate. Couples wanted their one child to be a male who would carry on the family name, so often female infants were simply abandoned, to be picked up by strangers or left simply to die. Some were “collected” by traffickers who sold them to orphanages, which then profited by putting them up for adoption abroad. Other children were simply seized from rural families as the equivalent of fines, and then offered to prospective adoptive parents outside the country as orphans—at a hefty price, of course.

Even that procedure, as unsavory as it might seem, was relatively benign compared to what was happening elsewhere. Forced sterilization and abortion was commonplace, sometimes through compliance prodded by a vast propaganda program, but often by compulsion of a far more physical kind. The number of victims, both the dead and the sad survivors, is simply incalculable.

Wang begins her investigation with her own family, interviewing her mother (who still believes that cannibalism would have occurred in China had the policy not been imposed by the party) and brother, who still feels guilty about how he was preferred over her. She talks to an uncle who weeps remembering the daughter he abandoned in the market, only to watch her die, and an aunt whose daughter was given up for adoption.

She then moves to a wider circle of locals, like the village head who presided—reluctantly, he says—in enforcement, and “public health” workers who actually performed operations, like a midwife who estimates she performed tens of thousands of sterilizations and abortions over the thirty-year period and who, under advice from a priest, now aids couples dealing with problems of infertility in order to make amends.

Wang continues her outward reach, interviewing traffickers who were punished for taking advantage of the policy and a journalist named Jiaoming Pang, now residing in Hong Kong, who left the mainland when his investigations revealed the horrors which the one-child policy caused. (Given the current state of affairs in Hong Kong, he might have to flee again before long.) Viewers should be warned that his photographs of abandoned fetuses left in landfills are deeply disturbing.

Having taken viewers down what might be described the circles of a man-made hell, Wang offers a measure of solace by discussing the work of American Brian and Long Lan Stuy, adoptive parents themselves, who have developed a database to try to reunite Chinese adoptees with their biological families. Using it she tries to find her aunt’s daughter, and in another case an adoptee reconnects with her twin sister in China.

Zhang also notes the replacement in 2015 of the one-child policy with another that prescribing two as the “perfect” number, and gives examples of the new propaganda campaign to promote the idea—made necessary by the reality that there are now simply too few young people to care for the country’s aging population—ironically, a result of the previous policy. Can the failure of one experiment in social engineering be corrected by another? Stay tuned.

In the meantime, this shattering documentary is hard to watch and hard to forget.