Separating identical from fraternal twins.
D001789:Blood Group Antigens; D001827:Body Height; D001835:Body Weight; D002648:Child; D005145:Face; D005190:Family; D005260:Female; D005306:Fertilization; D014644:Genetic Variation; D005824:Genetics, Behavioral; D005838:Genotype; D006197:Hair; D006801:Humans; D007498:Iris; D008297:Male; D010063:Ovum; D010641:Phenotype; D010858:Pigmentation; D011247:Pregnancy; D011795:Surveys and Questionnaires; D014427:Twins
D001789:Blood Group Antigens