Women worried that the move would only exacerbate discrimination from employers reluctant to pay maternity leave. Young people fumed that they were already hard-pressed to find jobs and take care of themselves, let alone a child (or three). Working-class parents said the financial burden of more children would be unbearable.

“I definitely will not have another child,” said Hu Daifang, a former migrant worker in Sichuan Province. Mr. Hu, 35, said he was already struggling, especially…