Some therapists call it "emotional anorexia," or learning to exist without relationships. A potential result of poor parental bonding, it's among the reasons for the apparent rise in casual sex, says Dr. Douglas Weiss, author of books such as "Intimacy: A 100-Day Guide to Lasting Relationships."

For such people, "the natural extension is to have casual encounters," Weiss says. "They're not really looking for a relationship."

Frequent casual sex seekers, he says, begin to mentally separate sex and relationships, seeing others as easily disposable. People become objects to toss away when they become inconvenient, "unless the person has some value, is serving them in some way."

For those who agree to be in such relationships, "what can happen is that they don't feel worthy of being loved in a long-term relationship," Weiss says. "They're used to being abandoned on a regular basis."

David Buss, a University of Texas psychology professor and author of "The Evolution of Desire: Strategies of Human Mating," says the rise of casual sex has strikingly different gender consequences. It makes men — typically on the pursuing end, as evidenced by a look at the personals page of your local weekly or Craig's List — more reluctant to commit to long-term relationships while being more likely to damage a woman's self-esteem than man's.

That's because studies show that women, in general, want some form of emotional involvement when it comes to sex. Those who took part in the "short-term mating" that accompanied the so-called Sexual Revolution of the late '60s and early '70s later described feeling "emotionally empty."

Meanwhile, he says, men were more apt to describe the period as a "golden age, often with a gleam in their eye."

Marc Ramirez: 206-464-8102 or mramirez@seattletimes.com