[Zygosity diagnosis in adolescent twins using questionnaires]

The validity of Zazzo's questionnaire method for zygosity determination has been tested within the framework of a study on twins. 11 (20.7%) of 53 monozygotic twin pairs were classified incorrectly. For the diagnosis of zygosity in adolescent twins, a questionnaire method has been designed and implemented in the G.D.R. With the help of this new method a relatively reliable zygosity determination is possible. A correct matching for 97% was obtained.