In diagnosing and preventing the birth of abnormal children the authors stress the necessity of team work of different specialists and their centralisation at the University complex or hospitals. The results of such a team work organised at the Division of Medical Genetics, Department of Gynecology and Obstetrics in Ljubljana and their experience in detecting some of monogenic, chromosome, and etiologically unknown disorders are presented, as well as the results of the follow-up of certain cases. The value of team work in genetic counselling is also pointed out.