Journalist, critic and writer. Married to Jessica Davis, editor in chief of Vogue. Rob Parker came to New York from California to try his hand at playwriting. Part of the radical Greenwich Village circle, he joined Sanger in helping to plan editions of The Woman Rebel and, according to other participants it was Parker who coined the term "birth control," which first appeared in the journal. Beginning in 1917 Parker also worked on the early issues of Birth Control Review and sometimes served as a ghostwriter for Sanger. In this period Parker also became the lover of Sanger's sister Ethel Byrne and remained her companion for many years. In addition to serving as a drama critic and contributor to periodicals such as Critical Opinion and The Arts, Parker became interested in popular religious movements and was the author of several biographies including A Yankee Saint (1935), a study of John Humphrey Noyes, and The Incredible Messiah (1937) which examined the Father Divine movement.