title: Intelligence-test results in opposite-sex twins.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D005260:Female; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D011247:Pregnancy; D012737:Sex Factors; D014427:Twins; D014429:Twins, Dizygotic