Do men under-value the scientific contributions of women? We study the effects of gender on the evaluation of economic research using data on submissions to four leading journals, matched to referee recommendations, editorial decisions, and subsequent citations. A customized name-matching algorithm allows us to classify the genders of 97% of all authors and referees with an error rate of under 1%. About one-fifth of submitting authors are female, though rates vary widely across subfields. The fractions of female referees are similar. We begin by examining whether editors are more likely to match a female-authored paper with a female referee, suggesting an awareness of possible gender differences in recommendations. We then address four main sets of questions. First, do male and female referees assess papers differently, and does the gender composition of authors matter for how different referees rate a paper? Second, how reliable are the assessments of male and female referees in predicting future citations, and does this vary with the gender of the authors? Third, how do editors weigh the recommendations of different referees against the information contained in prior publications and other author characteristics, including gender? Fourth, are there gender-related differences in the time that referees take to make a recommendation, or that editors take to reach an initial decision? We compare our findings to the results from a survey of economists, and use the survey results to help interpret the gender gaps in referees' and editors' decisions.