Based on well-known evidence on labor supply elasticities, several authors have concluded that women should be taxed at lower rates than men. We evaluate the quantitative implications of taxing women at a lower rate than men. Relative to the current system of taxation, setting a proportional tax rate on married females equal to 4% (8%) increases output and married female labor force participation by about 3.9% (3.4%) and 6.9% (4.0%), respectively. Gender-based taxes improve welfare and are preferred by a majority of households. Nevertheless, welfare gains are higher when the U.S. tax system is replaced by a proportional, gender-neutral income tax.