Tam Nguyen (Ryan Phuong – YS / Robert Wu – TBBT) is a Vietnamese-American Catholic boy who, in Young Sheldon, is Sheldon's classmate and only friend. His father Le Nguyen and mother Trang Nguyen run a store, Medford Mart. He has a troubled relationship with his parents, having been treated badly by both of them after moving to the United States. He has two sisters, Mai and Kim-Ly, with whom he has a good relationship. Tam laments his difficult childhood in war-torn Vietnam, which included his father being incarcerated in a re-education camp to "become a good communist", and his encounter with the Ku Klux Klan when he first arrived in America.