<p>We employ a self-reported survey measure of the ideal number of children to assess the impact of China’s one-child policy on couples’ childbearing. We take advantage of the novel feature of the self-reported measure that asks about couples’ preferences in a counterfactual setting to help identify the treatment effect of the one-child policy. The study estimates the policy’s treatment effect by using couples’ pre-policy ideal child numbers in 2014 and using the answer again in the post-policy period, under the assumption that the conditional distribution of the ideal number of children given the actual number of children is stationary without the policy constraint. Findings indicate a significant average reduction of 0.137 children per couple in 2014. Variations in policy effects are explored across educational, urban/rural, and occupational groups, with highly educated urban women in government jobs experiencing the most pronounced impact. Regional variations are also noted, mirroring policy stringency differences among provinces.</p>