There are several different concerns I think, firstly as pointed out by Murph and Sabre, there is demand for media which has sex in it. There is also the consideration that as Samnmax pointed out sexual repression is not a healthy attitude to take; look at the shocking treatment of woman in Saudi Arabia as a further example of what happens.
That however I think needs to be balanced with concerns for children and teenagers; I do think that there is (at least on UK tv) too much sexual content. Further more various studies do show that a high percentage of our teenagers get their body image and imaginations of what sex is life from pornography. This means, especially for girls and woman that there are unrealistic expectations of what they should look like from guys. (In studies, teenage boys are asked to identify real boobs and fake boobs - the continually pick the fake boobs (i.e. the plastic surgery crafted ones), while most boobs do not actually look like that.
Personally I do not think it is healthy that teenage boys should get their impression of what woman look like from pornography; again studies show instead of thinking pornography is a fantasy, they seem to think is a realistic depiction of sex. Quite how this matter is rectified is a matter of discussion.
With regards more "main stream" sex in the media; I do think that programmes viewable by children (at least in the UK) contain both too much sex and violence. This is to the extent that if I have kids today, I wouldn't let them watch terrestrial television until they were 13. Adverts are the greatest party guilty of his, over the usual programmes kids may watch; but for example quite how the Dark Knight was a 12 considering the level of violence in it, I don't know.
"Love is the only reality and it is not a mere sentiment. It is the ultimate truth that lies at the heart of creation." - Rabindranath Tagore
"Many a doctrine is like a window pane. We see truth through it but it divides us from truth." - Kahlil Gibran