[1][2] Her parents were first cousins from Lithuania who migrated to the United States as teenagers; she had one younger sister who died from erysipelas when Selna was four years old.
She completed a Master's degree and finished her PhD, with a thesis on vitamin E abnormalities in pregnant rats,[2] in 1953.
[2] Kaplan later became a professor of pediatrics at UCSF, a position that she held for almost 40 years, and was given emeritus status in 2000.
[1] Together, Kaplan and Grumbach developed numerous biochemical tests to measure hormone levels in children, babies, and fetuses.
[3] Kaplan died in San Francisco on July 21, 2010, after a long period of Alzheimer's disease.