Differences in height between siblings cannot be due to factors that siblings have in common. National Center for Biotechnology InformationU. Add to My Bibliography. Altogether, there were 1, sibships with 2 to 6 full brothers 4, persons, including 2, twins and 2, singletons. We used listwise deletion for handling missing data and 2-sided P values. The present study suggests that male twins born in Norway during — were slightly shorter in early adulthood than were singletons.
J Clin Psychiatry ;
The mother's total number of children was calculated using data from Statistics Norway. Adjustments were made for twin status, age at conscription, birth year, birth season, birth order, maternal and paternal educational levels, maternal age and marital status at delivery, and the mother's total number of children. Some studies of children or adolescents have suggested that the difference disappears during childhood 15. An analysis of the total study population using generalized estimating equations showed that the twins were 0. The treatment of sexual dysfunction in gay male couples. Psychoanal Study Child ; 2: