Sexual dysfunction among men under 40 is increasing, and the U.S. Navy thinks porn is to blame.

In a new review published in Behavioral Sciences, Navy urologists, neuroscientists and psychiatrists report that 15 years ago erectile dysfunction rates were negligible (2 to 5 percent) in sexually active men under 40. Now, the research indicates that rates are as high as 30 percent in this same age group.

It's not that all these men are unable to achieve erections. Many experience sexual dysfunctions such as difficulty climaxing, low sexual desire, and sexual dissatisfaction during partnered sex.

The Navy scientists uphold that this rapid increase in sexual dysfunctions in men under 40 cannot be adequately explained by smoking, diabetes, obesity, or cardiovascular disease – factors commonly associated with such problems in older men. None of these factors have increased proportionately during this time period. What has changed since 2006 is the widespread availability of broadband connectivity and – as a direct consequence – streaming porn.

The paper suggests that viewing porn may be especially problematic for those who start using it during key developmental periods of puberty and adolescence. The research indicates that the younger the age at which men are first exposed to internet porn, the greater their preference for it over partnered sex, the less enjoyment they report from partnered sex, and the more porn they use. This pattern of usage suggests that internet porn may be conditioning sexuality in ways which show up as sexual dysfunctions during partnered sex and debilitating distress in some men.

The paper advances a theory that the motivational systems of porn-watchers' brains are assigning undue importance to porn. This, in turn, can set up what is called a "negative prediction error" when users engage in sex with a partner. If real sex, even with a desired partner, registers as disappointing in comparison with internet porn use, the sexual centers of the brain may not produce adequate neurochemical response to attain and maintain an erection or climax without difficulty.

The authors are calling for more research, “intervention studies,” which would qualify and quantify how risky watching internet porn is for some otherwise healthy users.

The study warns that healthcare providers should not automatically assume that poor mental health is the cause of otherwise unexplained sexual dysfunction in men under 40. They suggest that a man who can achieve and sustain a satisfactory erection and climax as desired when masturbating without using internet porn, and only has difficulty when with a partner, likely has just a classic case of "performance anxiety." If, however, he cannot sustain an erection and climax without internet porn, the authors suggest the dysfunction is likely related to watching internet porn. The authors caution that false diagnoses of “performance anxiety” run the risk of prescribing needless psychoactive medications and phosphodiesterase-5 inhibitors, such as Viagra® or Cialis®.