In 1990, the economist Amartya Sen published an essay in The New York Review of Books with a bombshell title: “More Than 100 Million Women Are Missing.” His subject was the wildly off-kilter sex ratios in India, China and elsewhere in the developing world. To explain the numbers, Sen invoked the “neglect” of third-world women, citing disparities in health care, nutrition and education. He also noted that under China’s one-child policy, “some evidence exists of female infanticide.”

The essay did not mention abortion.