There will be other forms in addition to our classic marriage. One is already looming on the horizon: polyamory, or having more than one intimate partner.

I'm reminded of a female patient who was particularly aroused by the shape of her husband's shoulder. And this hint of perversion should ideally remain a secret for both partners.

The sexual revolution of the 1960s was mostly a movement of young people. I felt that the so-called "free relationships" were overrated.

Most pornographic images are simply too repulsive.

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.

There are young men who want thrills but no longer value sex, so they do completely different things, including aggressive things.

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.