Activity level and hyperactivity in twins.
D001294:Attitude to Health; D002648:Child; D002675:Child, Preschool; D004200:Diseases in Twins; D005260:Female; D005306:Fertilization; D005639:Frustration; D005824:Genetics, Behavioral; D005826:Genetics, Medical; D006167:Guilt; D006801:Humans; D006948:Hyperkinesis / Q000235:genetics*; D007223:Infant; D008297:Male; D009043:Motor Activity; D010063:Ovum; D010287:Parent-Child Relations; D010290:Parents; D012737:Sex Factors; D011795:Surveys and Questionnaires