About Mark

Mark P. Leondires, M.D., is Founder, Medical Director, and Partner in reproductive endocrinology at Illume Fertility and Gay Parents To Be, united as leading providers for family building both in the US and around the world. ​​Mark completed his residency in Obstetrics and Gynecology at Maine Medical Center in Portland, Maine, which was followed by a fellowship in Reproductive Endocrinology and Infertility at the National Institutes of Health in Bethesda, Maryland. After medical school, Mark served as the Director of Assisted Reproductive Technologies (ART) at the Combined Federal Program for Reproductive Endocrinology. While under his direction, the ART Program was one of the most successful in the Washington DC area and in the top tenth percentile nationally. During this time, he was an Assistant Professor at the Uniformed Services University of Health Sciences and clinical faculty for the Combined Fellowship in Reproductive Endocrinology. 

When Mark became a parent with his partner, he recognized the limited options available for family building for the LGBTQIA+ community. Mark decided to create and launch Gay Parents to Be; an educational resource that supports gay and lesbian couples and individuals making family building choices. 

Mark currently serves as a member of RESOLVE's Physician Council and a member of American Society for Reproductive Medicine’s (ASRM) Diversity, Equity & Inclusion Task Force. He is also the Past President of ASRM's LGBTQ Special Interest Group. He has been selected as a Castle Connolly Top Doctor in Connecticut and New York for many consecutive years. Mark regularly presents at conferences and organizations about fertility and family building, and remains passionate about advocating for access to care for all. 

As a member of the LGBTQ+ community and a parent to two children through egg donation and surrogacy, Mark combines his personal and professional experience to help a diverse range of patients become parents.