Influence of intrauterine relations on the intelligence of twins.
D000293:Adolescent; D001722:Birth Order; D001724:Birth Weight; D002648:Child; D005260:Female; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D012737:Sex Factors; D014427:Twins