How many young women cannot have children because of Chlamydia , how many(men and women ) are coping with AIDS . How many women are left literally "holding the baby" or going though the pain , and often guilt of abortion .
Here in the United States I often speak with theist who try to use the "We are more morale than atheist/agnostics" card. While there is no direct way to measure morality, there are certain factors at which we can look. For example, atheist have both lower rates of both STDs and also teen pregnancies then their Christian counterparts. And Christian women is six times more likely to have an abortion than atheist women.
In order to make good decisions you have to have a good model of how reality works. There are plenty of couples who watch pornography and still have a great sex life. Because they can talk about it openly and have good lines of communication. There are plenty of individuals who sleep around a lot and don't get STDs. Because they exercise safe sex practices. There are many men and woman who are comfortable in their bodies and don't feel sexually degrigated. Because they have learned to accept themselves for who and what they are.
The problem isn't that people are "too liberal". The problem is that, in a large part due to religion, many people think of human sexuality in negitive terms. They try to surpress their feeling and emotions which often leads to lower self esteem and greater liklyhood of taking unneccissary risks - like not using condoms or other kinds of protection.
When we accept who we are - then we can make good decisions. But when we reject who we are - it's a recipe for disaster.
Sex is a naturall part of being human. If you want to share it with just one person - that's a beautiful and wonderful thing. If you want to sleep around a lot and you are honest with your partners - that's great too. Not everyones the same. And no one should be advocating that we all should be.