Dr Simpson is the founding Chair at Florida International University Miami, and has served as Chair and Professor in numerous universities in the USA. Besides, he has played leadership roles in many professional organizations. His research encompasses many areas of genetic prenatal diagnosis and reproductive genetics.
He was 1993-1994 President of the American Society for Reproductive Medicine, 1994-1998 President of the International Society of Prenatal Diagnosis, 1998-1999 President of the Society for Gynecologic Investigation, 2007-09 President of the American College of Medical Genetics, 2006-09 President of the Preimplantation Genetic Diagnosis International Society He is a member of the National Academy of Sciences, Institute of Medicine (IOM).