People have been fretting about the “population problem” for at least fifty years. But over those five decades, the perceived problem has practically reversed. From the sixties to the eighties, the problems on people’s minds were overpopulation and the “population explosion.” The proposed solutions were usually government programs ranging from mild nudges (like free condoms and sex education) to horrific coercion (like India’s involuntary sterilizations and China’s one-child ...