Time magazine has a cover story “Pornography and its threat to virility”, here online (paywall), and in print, in the Aoril 11, 2016 issue, p. 40, with tagline “Why young men who grew up with Internet porn are becoming advocates of turning it off.” Time had a story on porn in April 1976, “The Porno Plague”.
The basic report concerns young men becoming impotent or unable to have erections in real sex with women after porn addiction. There may even be physical changes in the brain when teens or younger men get used to porn.
So one can even imagine that porn addiction lowers the birth rate.
There is a law being proposed in Britain that would have resembled COPA in the United States, and lawmakers have not considered how adult-id verification could be very reliable.
Back in 1986, I recall a religious tract at LAX airport that stated that people who become satiated with porn will no longer be able to have “real” marital sex.
But in earlier generations, one concern that straight men living around men they knew were gay, in college dorms (before Stonewall) wasn’t being “approached” but merely that being “scoped” could make them self-conscious and unable to perform heterosexually when the time came. This was a hidden concern with the military in the early years of “Don’t Ask. Don’t Tell”.
Update: April 10
The Washington Post reinforced this idea today with an article by Gail Dines, maintaining that porn is a public health problem.