Premise: John Davison Rockefeller III (March 21, 1906 – July 10, 1978) was a philanthropist and third-generation member of the prominent Rockefeller family. He was the eldest son of philanthropists John D. Rockefeller Jr. and Abby Aldrich Rockefeller. His siblings were Abby, Nelson, Laurance, Winthrop, and David.
Hypothesis: John Davison Rockefeller III was an only child.