title: Intrapair variations in intelligence test scores among mentally retarded monozygotic and dizygotic twin pairs reared apart.
mesh_terms: D002668:Child Rearing; D002674:Child, Institutionalized; D004200:Diseases in Twins; D005260:Female; D005823:Genetics; D006801:Humans; D008607:Intellectual Disability / Q000209:etiology; D007360:Intelligence; D008297:Male; D011247:Pregnancy; D012737:Sex Factors; D012931:Social Environment; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic