title: Maternal ABO groups and the sex ratio of live births.
abstract: The sex ratio of 67,205 single, live births was significantly associated with maternal ABO, but not Rh, types. The proportion of males was highest among children of AB mothers in both the Rh+ and Rh- subpopulations, corroborating previous data. The findings are discussed with relation to earlier reports and possible mechanisms.
mesh_terms: D000017:ABO Blood-Group System; D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D012204:Rh-Hr Blood-Group System; D012744:Sex Ratio
chemical_list: D000017:ABO Blood-Group System; D012204:Rh-Hr Blood-Group System