A BillionToOne co-founder, Oguzhan believes that diagnostics can be made much more powerful, accurate, and affordable if they are engineered to be quantitative. Oguzhan helped develop our proprietary molecular counting platform. He has led the Company since its inception and raised more than $200M in funding including from venture capital funds and investors who previously invested in tech companies such as SpaceX, Box, Spotify, Palantir, Braintree, and biotech companies such as Counsyl, WebMD, and Omada Health.Oguzhan received his PhD from Stanford University, where his work was published on the Cover of Cell Systems. He graduated summa cum laude and Phi Beta Kappa from Princeton University with a bachelor’s in molecular biology and minors in physics, computer science, and applied mathematics.

Lisa joined BillionToOne in September of 2023. Recognized nationally as an expert in population-based carrier screening and has published extensively on Ashkenazi Jewish genetic disorders, Lisa has developed several novel test methods, including the identification of individuals that are at increased risk of being silent carriers for spinal muscular atrophy as well as the use of genetic ancestry in pan-ethnic carrier screening. With more than 18 years of experience as a clinical laboratory leader and CLIA director, Lisa was a co-founder of Sema4 and held the title of Chief Diagnostics Officer from 2017 to 2022. Prior to her time at Sema4, Lisa was the Executive Director of the Mount Sinai Genetic Testing Laboratory.Lisa received her Ph.D. in Molecular Genetics from The Albert Einstein College of Medicine and received her fellowship training from the Icahn School of Medicine at Mount Sinai where she became board certified in Clinical Molecular Genetics and Clinical Cytogenetics. Lisa currently holds the academic title of Associate Professor in the Department of Genetics and Genomic Sciences at Mount Sinai.

Bethany Tucker is a certified genetic counselor who joined BillionToOne in 2021 and now serves as a senior medical science liaison. She brings more than 25 years of experience spanning prenatal and pediatric genetics, fetal care, and population-based genomic screening. Before joining BillionToOne, Bethany held senior roles at Sanford Health and the Colorado Fetal Care Center, with earlier experience at the University of Colorado and Reproductive Genetics Center. She earned both her MS in Genetic Counseling and her MBA from the University of Colorado.

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Caitlin Mann, MGC, CGC is a Prenatal Medical Science Liaison at BillionToOne. Prior to joining BillionToOne, she spent 11 years at Vanderbilt University Medical Center in the Division of Maternal-Fetal Medicine, serving as both a clinical genetic counselor and Assistant Director of Obstetrical Genetic Counseling. Caitlin earned a B.A. in Biology and Spanish from Illinois Wesleyan University in 2012 and a Master of Genetic Counseling from the University of Maryland in 2014. Originally from Chicago, she has called Nashville, TN home for more than a decade. She is passionate about reproductive justice and advancing equitable, patient-centered care in women’s health, a commitment that continues to shape the work she pursues.

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Jennifer joined BillionToOne in July 2020. As a certified genetic counselor with over 17 years of clinical experience, Jen is committed to ensuring patients and providers are supported and educated about the options and utility of prenatal testing.

Jen joins BillionToOne after 17 years as a prenatal genetic counselor at UTHealth where she led a team of genetic counselors providing patient care in MFM clinics across the city of Houston. Jen has extensive volunteer and leadership experience within national societies such as American College of Obstetrics and Gynecology and National Society of Genetic Counselors.

She served as president of NSGC in 2014.Jen earned her MS in genetic counseling from the University of Texas Health Science Center in Houston and her Bachelor of Science in Biology with a minor in Chemistry from Truman State University.

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Rachel Doyel is a board-certified, licensed genetic counselor with extensive clinical and industry experience in prenatal and reproductive genetics. She joined BillionToOne in January 2023. After beginning her career in clinical genetic counseling, Rachel transitioned to a medical science liaison role at Ariosa Diagnostics, where she supported education and implementation of the Harmony Prenatal Test, with an emphasis on equitable access to noninvasive prenatal testing for aneuploidy. She later expanded her expertise in women’s health at Sema4, providing educational and clinical support across a broad portfolio of reproductive molecular diagnostics. Rachel earned her master’s degree in medical and molecular genetics from Indiana University and is an active member of the Indiana Network of Genetic Counselors.

Rachel Mercado, MS, CGC, is a Medical Science Liaison at BillionToOne with over five years of experience in germline and somatic genetics, oncology, and precision diagnostics. She began her career as a clinical genetic counselor specializing in pediatrics before transitioning to medical affairs, where she now supports the clinical application of liquid biopsy technologies. Rachel specializes in translating complex genomic data into practical insights, helping providers make informed decisions around targeted therapies and disease monitoring.

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Vicky Hsieh, MS, CGC is a board-certified genetic counselor and Medical Science Liaison at BillionToOne. Prior to joining BillionToOne, she spent eight years at SUNY Downstate Medical Center, where she served as Director of Genetic Services and gained extensive experience in prenatal genetics, newborn screening, and the clinical application of genetic testing across specialties. In her current role, Vicky partners with healthcare providers to provide education on emerging technologies and advances in prenatal genetic screening and testing.