Carlos Paton Blacker (also C. P. Blacker) was a war hero of both World War I and World War II. He was also a physician and a prominent eugenist.
When Margaret Sanger established the International Planned Parenthood Federation (IPPF) in 1953,  he left his post as secretary of the Eugenics Society and became the first administrative chairman of the IPPF.
Blacker came to believe that the best way to achieve eugenic goals was to promote medically managed birth control. This caused some disputes within the Eugenics society, because some members feared that birth control should only be used by the "unfit", while the "betters" should not limit their breeding.