In a cohort study of 234 twin pairs followed from pregnancy to 12-20 years of age the psychosomatic symptoms of adolescents were inquired from their parents. Girls had symptoms more often than boys. Intrapair concordances were high. The mothers' favorite children had psychosomatic complaints more often than the father's favorites or those who were equally close to each parent. Psychosomatic complaints were more frequent in the submissive members of twin pairs and nervous symptoms in the dominant ones.