Born in Berlin, Germany, Sanger came from a devoutly Jewish family which moved to the United States in about 1878.
Sanger was further educated in painting at the Art Students League of New York and the Artists-Artisans Institute.
In a statement before the Court of Special Sessions in New York City on September 10, 1915, William Sanger identified emotionally with his wife's work and referred to Anthony Comstock as a victim of "incurable sexophobia" who lacked "the intelligence to distinguish between pornography and scientific information.
If some persons would go around and urge Christian women to bear children, instead of wasting their time on woman suffrage, this city and society would be better off."
The judge's statement intensified interest in the case and redefined the issue as a dispute about women's roles rather than about obscenity as was previously viewed through the anti birth control propaganda of Anthony Comstock.