Single gene mutations may lead to an inherited disorder with Mendelian inheritance patterns, of which over 8,000 disorders have been catalogued. The strategy of population screening, offering genetic counseling, prenatal diagnosis and termination of affected pregnancy has been successfully applied worldwide to reduce the number of new patients. Common fetal sampling techniques in utero include chorionic villous sampling, amniocentesis, and fetal blood sampling. Then appropriate analysis is applied for diagnosis, where karyotyping is mainly for chromosome abnormalities and PCR is for single gene disorders. Several modern molecular techniques are useful for identification of defects in single genes. Preimplantation genetic diagnosis is an advanced alternative giving the couple the chance to start a pregnancy ensuring that the baby is free from the genetic disease. It is the role of obstetricians to make most use of the advance molecular biology knowledge to have a healthy community.

Keywords: Chromosome abnormalities, Down’s syndrome, Embryo selection, Molecular biology, Polymerase
chain reaction (PCR), Preimplantation genetic diagnosis (PGD), Prenatal diagnosis (PND)