Current concepts on the role of genetic factors in the development of schizophrenia and on the relative risk for this disease and spectrum disorders are reviewed. An analysis of the results of genetic counseling of 120 subjects revealed that, comparing to other mental disorders, patients with schizophrenia or relatives, mostly those having a schizophrenic parent (40%) or spouse (25%), referred more frequently for a consultation. Most of the referrals (70%) had a high educational level. As it was found out during the counseling, up to 20% of the relatives met a diagnosis of psychiatric disorders, mostly personality disorder (9%) and depressive state (7%). Psychological testing with personality inventories revealed a high level of personality abnormalities (schizoid--22%, hyperthymic--16% and obsessive-anxiety--4%) in 43% close relatives of patients seeking medicogenetic advice. The genetic counseling featured by the use of the comprehensive approach, basing on all obtained data (psychiatric, psychological, neurophysiologic etc.), that increases its accuracy and may assist families in taking a reasonable decision in birth planning.