Meanwhile, the U.S. teen pregnancy rate has plummeted to a third of its modern high. When this decline started, in the 1990s, it was widely and rightly embraced. But now some observers are beginning to wonder whether an unambiguously good thing might have roots in less salubrious developments. Signs are gathering that the delay in teen sex may have been the first indication of a broader withdrawal from physical intimacy that extends well into adulthood.
That turn-offs matter more than turn-ons may sound commonsensical, but in fact, this insight is at odds with most popular views of sexual problems. When people talk about addressing a lack of desire, they tend to focus on fuel, or stimulation—erotica, Viagra, the K‑Y Jelly they were handing out at the New Brunswick student-health center. These things are helpful to many people in many cases, but they won’t make you want to have sex if your brakes are fully engaged.
As one might imagine, feeling comfortable in your body is good for your sex life. A review of 57 studies examining the relationship between women’s body image and sexual behavior suggests that positive body image is linked to having better sex. Conversely, not feeling comfortable in your own skin complicates sex. If you don’t want your partner to see you getting out of the shower, how is oral sex going to work?
Many fish change sex over the course of their lifespan, a phenomenon called sequential hermaphroditism. In clownfish, smaller fish are male, and the dominant and largest fish in a group becomes female. In many wrasses the opposite is true—most fish are initially female and become male when they reach a certain size. Sequential hermaphrodites may produce both types of gametes over the course of their lifetime, but at any given point they are either female or male.
The pleasure of sex arises from many factors including the release of neurochemicals such as oxytocin and dopamine, which flood the system during orgasm, as well as the sense of connection communicated by touching, massaging, and cuddling. Given the enormous variability in activities that people find arousing, there is no one way to be sexual. Men are especially stimulated by visual imagery, and about 90 percent of young men report using pornography with some regularity, often because they lack a partner or don't know how to bridge the differences in sexual appetite and interest that can occur between partners in the absence of discussion of their sexual pleasures. Many people engage in behaviors that were once perceived as atypical, such as dominance play and anal intercourse. Researchers know that flexibility in sexual repertoires is healthy and generally enhances relationships; they regard a specific behavior as problematic only when it creates harm or distress for one or both partners or when the behavior is compulsive—that is, it becomes the only means of arousal. "Sex addiction" is a label often used to suggest excessive interest in sex, but studies show it may be more related to the moral/religious environment in which a person lives.