John Williams, III, MD is Director of Reproductive Genetics and interim Director for the Division of Maternal-Fetal Medicine within the Department of Obstetrics and Gynecology at Cedars-Sinai Medical Center. Dr. Williams is also a Professor of Obstetrics and Gynecology at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA).

Dr. Williams is board certified in obstetrics and gynecology, maternal-fetal medicine, medical genetics and clinical cytogenetics. He is a member of several professional organizations, including the American College of Medical Genetics, American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine and the Society for Maternal-Fetal Medicine.

Dr. Williams' name is synonymous with chorionic villus sampling (CVS), having performed over 16,000 procedures -- the largest of any practitioner west of the Mississippi. A prolific writer, Dr. Williams has written articles for numerous peer-reviewed publications, such as the American Journal of Obstetrics and Gynecology, Obstetrics and Gynecology, Prenatal Diagnosis and the American Journal of Medical Genetics. He has written book chapters on the subjects of amniocentesis, chorionic villus sampling and ultrasound screening to determine the gestational diabetic at risk for macrosomia and labor dystocia.

Dr. Williams received his bachelor's degree from San Jose State University and his medical degree from the UCLA School of Medicine. He completed his internship and residency in obstetrics and gynecology at Harbor/UCLA Medical Center, as well as his fellowship in maternal-fetal medicine and in medical genetics.