I can recommend a book review called "How sexual perversion became the new norm" which is online at the 'New Statesman' site. (Google it!)
It actually reviews two new books: 'Perv: the Sexual Deviant in All of Us' by Jesse Bering (Doubleday), and 'The Pleasure's All Mine: a History of Perverse Sex' by Julie Peakman (Reaktion)
Being a sexual pervert (or fantasist) myself, I was struck by this:
'... How did we become, Bering asks, "the insufferably judgmental homonids that we are" and "why don't we empathise with, rather than judge, others?
'Jesse Bering and Julie Peakman are probably the most tolerant people who have ever lived, next to the Greeks who inhabited a libertine utopia where every philia, from bird sex to incest, was given the green light ...
'... [T]he most challenging chapter in Perv is on the varying age of consent (14 in Chile, 13 in Argentina, 12 in Mexico, 18 in Turkey, 15 in Sweden, and so on) ...'
The books themselves should be readily available, both being from leading publishers.