Meet our IVF & Andrology Lab Staff Members

Liesl Nel-Themaat, Ph.D.

Title: Senior Embryologist and Endocrinology Lab Supervisor
Primary Location: Denver

Liesl Nel-Themaat, Ph.D., UC Denver ARM Senior Embryologist and Endocrinology Lab SupervisorDr. Liesl Nel-Themaat joined Advanced Reproductive Medicine in 2016 as a senior embryologist and endocrinology lab supervisor. She graduated with a Bachelor of Science from Stellenbosch University in South Africa, and received her Ph.D. in assisted reproduction from Louisiana State University. Her graduate studies focused on advanced reproductive technologies in endangered species at the Audubon Nature Institute in New Orleans.

After completing a postdoctoral fellowship studying post-implantation embryos at M.D. Anderson Cancer Center in Houston, TX, she worked as a clinical embryologist at Reproductive Biology Associates in Atlanta. She moved to Colorado in 2011 to work at Colorado Reproductive Endocrinology.

Liesl enjoys an active lifestyle with her husband and two children. She can be found snowboarding, mountain biking, golfing and painting for local galleries in her free time.

Melissa Rosario, BA, T.S. ABB

Title: Senior Embryologist and Andrologist
Primary Location: Denver

Melissa Rosario | Advanced Reproductive MedicineMelissa has been working in the andrology and embryology laboratories at Advanced Reproductive Medicine since 2002. She has a Bachelor of Arts in Molecular Biology from Pomona College and spent 10 years pursuing academic research on multidrug resistance and pulmonary models of inflammation before switching to clinical duties. Melissa has been certified by the American Board of Bioanalysis (ABB) as a Technical Supervisor since 2007, and has been certified as a Reproductive Lab Inspector by the College of American Pathologists.

Melissa enjoys the active Colorado lifestyle and likes to learn new outdoor skills, such as tennis, scuba diving and triathlon training.

David Russell, B.S., T.S. ABB

Title: Embryologist and Andrologist
Primary Location: Denver

David RussellDavid received his Bachelor of Science in Biology from the University of New Mexico in 1987. He moved to Denver in 1989 and performed research at National Jewish Medical and Research Center and The University of Colorado Health Sciences Center. His research at NJMRC was in the field of immunology. He was also involved in the production of genetically engineered mice using targeted mutagenesis in mouse embryonic stem cells. David was recruited from National Jewish Medical Center in 2001 to work as a clinical embryologist at the University of Colorado. He is certified as a Technical Supervisor in Embryology and Andrology through the AAB.