Behavioural genetics of early childhood: fears, restlessness, motion sickness and enuresis.
Seventy-nine pairs of same-sex twins were examined at the age of three years at a municipal clinic and their mothers were interviewed to assess the twins' current and past behaviours. The zygosity was determined after the interview by fingerprints and/or bloodtyping in the majority of cases. The following significant differences in concordance between monozygotic and dizygotic twins were found: fear of strangers during observation at the clinic; marked fear of strangers in the first year of life; whether or not the child was startled by sudden noises during infancy; whether or not the child was able to sleep alone at three years without a parent sitting nearby; susceptibility to motion sickness; nocturnal enuresis; short attention span or restlessness during the test.
D002653:Child Behavior Disorders / Q000235:genetics*; D002675:Child, Preschool; D004200:Diseases in Twins; D004775:Enuresis / Q000235:genetics; D005239:Fear; D005260:Female; D005824:Genetics, Behavioral; D006801:Humans; D009041:Motion Sickness / Q000235:genetics; D011247:Pregnancy; D011595:Psychomotor Agitation / Q000235:genetics; D014427:Twins / Q000523:psychology*; D014429:Twins, Dizygotic / Q000523:psychology; D014430:Twins, Monozygotic / Q000523:psychology