title: Bloodtyping and twin zygosity.
mesh_terms: D000293:Adolescent; D000483:Alleles; D001789:Blood Group Antigens; D005260:Female; D005306:Fertilization; D005787:Gene Frequency; D005826:Genetics, Medical; D005838:Genotype; D006801:Humans; D007223:Infant; D007519:Isoantigens / Q000032:analysis; D008297:Male; D010063:Ovum; D010641:Phenotype; D011247:Pregnancy; D012204:Rh-Hr Blood-Group System / Q000032:analysis; D014427:Twins
chemical_list: D001789:Blood Group Antigens; D007519:Isoantigens; D012204:Rh-Hr Blood-Group System