Single-sex education refers most generally to education at the elementary, secondary, or postsecondary level in which males or females attend school exclusively with members of their own sex. This report deals primarily with single-sex education at the elementary and secondary levels. Research in the United States on the question of whether public single-sex education might be beneficial to males, females or a subset of either group (particularly disadvantaged youths) has been limited. However, because there has been a resurgence of single-sex schools in the public sector, it was deemed appropriate to conduct a systematic review of single-sex education research. A number of theoretical advantages to both coeducational (CE) and single-sex (SS) schools have been advanced by their advocates, a subset of whom have focused specifically on the potential benefits of SS schooling for disadvantaged males who have poor success rates in the educational system.