When Quillen received his Ph.D. at the age of 24, he and his wife Jean, a violinist, were already caring for two of their five children.
Kapag Quillen natanggap ang kanyang Ph.D. sa edad na 24, siya at ang kanyang asawa Jean, isang byolinista, ay na-aasikaso para sa dalawang ng kanilang limang mga anak.