Individual differences in breast size are a conspicuous feature of variation in human females and have been associated with fecundity and advantage in selection of mates. To identify common variants that are associated with breast size, we conducted a large-scale genotyping study in 7,169 European women across 3 independent sample collections.  As it may be difficult to judge breast size using bra size due to poor fit, unreliable size charts, lack of an industry standard, and possible “vanity sizing”, we measured the total area of the breast imaged on mammograms, which are X-rays of the breasts used for routine breast cancer screening. We report a new locus at 22q13 (rs5995871, P = 3.2 × 10−8), and confirmed previous GWAS findings for breast size at four other loci. (By Dr. Jingmei Li, http://jmg.bmj.com/content/early/2013/07/02/jmedgenet-2013-101708 )