A generic term for any unfounded assertion about the (adverse) effects of masturbation.
Masturbation myths; it (allegedly) causes
• Growth of hair on one’s palms
• Impotence in later life
• Mental illness
John Harvey Kellogg, of cornflakes fame, believed masturbation led to leprosy, tuberculosis, heart disease, epilepsy, shyness in some people, unnatural boldness in others, a fondness for spicy foods, round shoulders, acne, insanity, idiocy, and death.