Phyllis O. Whitten's 1976 compilation a Fogg data shows one child for Ellis Whitney Fogg, a son, Robert Ellis Fogg, born 10 Jan 1921 in Chicago. She says that Robert married Marilyn Ruth Walker in June 1948, and reports her parents. "Robert is a mechanical engineer. He is active in church work with his wife, and interested in art and sports. Marilyn enjoys art and music. Res: Wilmington, Del.; Houston, Texas" This level of detail suggests that Mrs. Whitten was in contact with Robert and thus that the lack of a listing of children might imply that there were none. You might want to e-mail her son, Geoffry Whitten at firstname.lastname@example.org.
There's an SSDI entry for Robert E. Fogg, born 10 Jan 1921, died 16 Feb 1998, last residence Laguna Hills, Orange County, California.