Etta Angell Wheeler was the rescuer and advocate of Mary Ellen Wilson, whose infamous abuse story led to the creation of the New York Society for the Prevention of Cruelty to Children. Wheeler was also influential in the society's creation because she convinced future founder of the society, Henry Bergh, who at the time was founder of the American Society for the Prevention of Cruelty to Animals, to take on the issue and spearhead the case.

Mary Ellen Wilson, also called Mary Ellen McCormack, was an American victim of child abuse whose case led to the creation of the New York Society for the Prevention of Cruelty to Children, the first child protection agency in the world. At the age of eight, she was severely abused by her foster parents, Francis and Mary Connolly. Because she was assisted by Henry Bergh, then the head of the American Society for the Prevention of Cruelty to Animals, some sources incorrectly state that statutes against cruelty to animals had to be used to remove her from the home. Hers was the first documented case of child abuse in the United States.