We calculate the harm a birth imposes on others when greenhouse gas emissions are a problem and a cap limits emissions damage. This negative population externality, which equals the corrective Pigovian tax on having a child, is substantial in calibrations. In our base case, the Pigovian tax is 21 percent of a parent's lifetime income in steady state and 5 percent of lifetime income immediately after imposition of a cap, per child. The optimal population in steady state, which maximizes utility taking account of the externality, is about one quarter of the population households would choose voluntarily

Women may want greater taxes and redistributional spending than men if malein comes exceed female incomes and men and women are not always married. Cross-section evidence from opinion polls provides indirect support for this view.Women express greater favorability toward redistributional spending than do men; the difference is explained largely but not entirely by income differences. The empirical analysis provides partialsupport for Meltzer and Richard (1981) , and suggests that increases in singleness after World WarII may have acted to increase differences by sex in desired redistributional spending.