title: Development of Piagetian logicomathematical concepts: preliminary results of a twin study.
mesh_terms: D001076:Aptitude; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D004522:Educational Status; D005191:Family Characteristics; D005260:Female; D005823:Genetics; D005824:Genetics, Behavioral; D006801:Humans; D008297:Male; D008433:Mathematics; D011247:Pregnancy; D012067:Religion; D012923:Social Class; D012931:Social Environment; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic