IN THE 1990s, when the internet was for nerds, as many as half of all web searches were for sexually explicit material. That share has fallen—but only because everything from home-buying to job-hunting has moved online. Pornography still accounts for more than a tenth of all searches. The number of porn pages is estimated at 700m-800m; one of the biggest sites claims to get 80 billion video views a year.

Whenever pornography becomes more available, it sparks a moral panic. After the advent of girlie magazines in the 1950s, and X-rated rental films in the 1980s, campaigners claimed that porn would dent women’s status, stoke sexual violence and lead men to abandon the search for a mate in favor of private pleasures. Disquiet about the effects of online pornography is once more rising (see article). Most of it is now free. As commercial producers fight over scarce revenue, their wares are becoming more extreme. Because of smartphones, tablets and laptops, hardcore material can be accessed privately by anyone. The result is that many teenagers today have seen a greater number and variety of sex acts than the most debauched Mughal emperor managed in a lifetime.

oo little is known about porn in particular and sexuality in general to judge what effect this will have. Prudishness and fear of controversy mean that funding bodies often shy away from sex studies. A survey in 2013 by British researchers found more than 2,000 papers related to the effects of porn on teenagers. Only 79 based their conclusions on solid evidence.

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