He contributed four major achievements to his field of work: 1. The construction of the Hungarian Congenital Abnormality Registry (1970) which has long been considered one of the most acknowledged registers of its kind. 2. The establishment of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980) which was the first and remains the largest case-control database for the analysis of fetal exposures to environmental factors, maternal diseases and maternal drug use. 3. The organization of a complex system for periconceptional care as a scientific approach to the preparation for conception and the protection of early fetal lives. 4. The design of the double-blinded case-control study for the prevention of the first occurrence of neural-tube defects using periconceptional multivitamins containing folic acid, which has also showed a preventive effect in urinary tract and heart defects.