Some 95 percent of all sexual contact still occurs in permanent relationships. That's an impressive number.

I maintain that we are still a largely ignorant society when it comes to sex. We speak incorrectly and superficially about sexuality. And when you talk about it too much, you run the risk of destroying its mystery.

Sexual desire declines after four to seven years. That's been proven.

Just go to an auto show, and you'll see all the signs of sexual arousal in the men: shiny eyes, tremors, sex flush. An acute example of the need for professional sex research.

The social problem is that we haven't come up with any alternative models. Our culture hasn't developed an ars erotica. Think, for example, of conditions in India or in Japanese culture and of how the erotic has been cultivated there. They're not as clinical and rabbit-like as we are.

I will always be referred to as a theorist, but I was only a fellow traveller with a degree.

Some 95 percent of all sexual contact still occurs in permanent relationships. That's an impressive number.