Clinical psychologist Dr Tanya Byron asks why we judge some expressions of sexual desire as eccentric but within normal bounds, and condemn others as repugnant and dangerous. Tanya spends time with a self-described sex addict who has had more than 5,000 partners; he insists he is normal and argues that most men would do the same if given half the chance. She meets a woman who insists that a low libido is the norm, and that most women want far less sex than their male counterparts. Tanya also confronts the case of a man who believes there should be no age of consent.