Weeraratna was born in Sri Lanka and raised in Lesotho.[1] From the age of 15, she wanted to become a cancer researcher.[2] In 1988, due to apartheid,[2] Weeraratna left Southern Africa at the age of 17 to study biology at St. Mary's College of Maryland.[1] She earned a bachelor's degree in 1991. Weeraratna obtained a Master's in Philosophy from George Washington University in 1997, during which time she met the Hand. She earned a doctorate in Molecular and Cellular Oncology from the Columbian College of Arts and Sciences of the George Washington University Medical Center.