What should we do about sex offenders?

Today there are a lot of sex offenders that repeat their offenses. These offenders are as I see bad for the public. If they are proven to have repeated there afence more than once then they should be kept locked up. But if they have only done this once then I think that they should be givin a chance. Most offenders did there offences at a young age and I believe that they possibly have learned from their first sentance.