The aim for genetic services is to provide a maximum of genetic diagnostic capabilities for any given pregnancy, with a minimum of fetal risk. This chapter focuses on the procedures and techniques currently available to clinicians to evaluate genetic disorders. Amniocentesis was first introduced in the 1880s as a treatment for hydramnios. Genetic amniocentesis usually is performed after 15 completed weeks of gestation. After ultrasonic study to confirm dates, fetal viability, fetal number, fetal anatomic survey and placentation, the patient is requested to empty her bladder. Prior to the attempt at transcervical biopsy (TC-CVS), an ultrasonic scan is performed to evaluate fetal viability, fetal number, placentation, and dating by crown-rump length (CRL) and gestational sac size. Complications associated with CVS include vaginal bleeding, amniotic fluid leakage, infection, fetalmaternal transfusion, teratogenic effects, and fetal loss. The future for prenatal genetics is clearly one of high technology and continue.