I. INTRODUCTION.
D000124:Achievement; D000293:Adolescent; D041923:Adolescent Development; D002648:Child; D002657:Child Development; D002755:Choice Behavior; D005260:Female; D005783:Gender Identity; D006801:Humans; D007206:Individuality; D008297:Male; D008433:Mathematics; D008960:Models, Psychological; D009042:Motivation; D009146:Music; D010287:Parent-Child Relations; D011932:Reading; D012649:Self Concept; D012737:Sex Factors; D012951:Socialization; D013177:Sports