As has been mentioned I think partly it's because sex crimes are talked about more often when I was young no one said the words molestation, rape, or sexual abuse. And pat of it is a media we have now that needs the worse of the worse crimes on air or in print to make the sell, which as much as I loathe the media some times it's a good thing to have pedophiles caught and reveled, they succeed when there is a cover-up. So we probably are hearing more about child abuse cases a diease that has been around forever.
My personal reason I think we have a lot of child abuse is because children are not valued high enough, priority needs to be placed on 'keeping' offenders out of communities, society has been too linient with letting offenders back on the streets, Tougher laws need to be inacted and child preditors need to be treated accordingly. Pedophiles are not cured and once released they re-offend and at times it's allowed to go on and on. The justice system needs to kick in and protect the ones worth protecting, not giving rights to pedophiles who gave there rights up when they chose to harm children.