The diagnosis of twin zygosity.
D000017:ABO Blood-Group System; D000293:Adolescent; D001789:Blood Group Antigens; D001827:Body Height; D001835:Body Weight; D005123:Eye; D005260:Female; D005796:Genes; D006197:Hair; D006801:Humans; D011247:Pregnancy; D012204:Rh-Hr Blood-Group System; D014427:Twins
D000017:ABO Blood-Group System; D001789:Blood Group Antigens; D012204:Rh-Hr Blood-Group System