ABO and Rh blood groups in relation to sex ratio of sibs.
D000017:ABO Blood-Group System; D000293:Adolescent; D001782:Blood Donors; D002648:Child; D002675:Child, Preschool; D005260:Female; D005828:Genetics, Population; D006801:Humans; D008297:Male; D012204:Rh-Hr Blood-Group System; D012606:Scotland; D012744:Sex Ratio
D000017:ABO Blood-Group System; D012204:Rh-Hr Blood-Group System