Career
Born in Dublin, from landed gentry, he was raised in England from the age of 7. His father was an eminent surgeon who moved to private practice in London, and Mapother completed his own Doctor of Medicine in 1908. He undertook locum work in mental asylums and then served in the medical corps during World War I, developing an interest in shell shock.
Mapother married Barbara Reynolds in 1915.
Nevertheless he appears to have been homosexual. He was involved in activities of the Eugenics Society and was often consulted about abortions for poor women.