HAMILTON, L. H., J. BROOKS-GUNN, M. P. WARREN, and W. G. HAMILTON. The role of selectivity in the pathogenesis of eating problems in ballet dancers.Med. Sci. Sports Exerc., Vol. 20, No. 6, pp. 560–565, 1988. Forty-nine dancers from four national ballet companies in America (N= 32) and the People's Republic of China (N= 17) were surveyed (mean age, 24.6 ± 4.18) from highly and moderately selective dance companies. The less selected American dancers reported significantly more eating problems (46% vs 11%;P< 0.05), anorectic behaviors (2.77 vs 1.11;P< 0.05), and familial obesity (42% vs 5%;P< 0.05) than the Americans chosen from a company school. Differences were not found on these variables between the highly selected American and Chinese dancers. All of the groups reported a delay in menarche and weighed approximately 14% below their ideal weight for height. These data suggest that dancers who have survived a stringent process of early selection may be more naturally suited to the thin body image demanded by ballet and so less at risk for the development of eating problems. In addition, delayed menarche is typical of the majority of national dancers and probably is reflective of genetic and environmental factors.