There really is no easy answer when it comes to disclosure. One of my Ts (and yes I had several) said that the way we deal with trauma is by communicating the trauma over and over again until it no longer has the same power over you that it did. Like for instance, if you got to work after an accident, what would you do to make yourself feel better? You communicate the trauma with anyone that will listen. Of course some people have more private dispositions than others but this is usually the case. Using this logic I would say to go ahead to communicate the abuse with your parents as it will aid you in healing even if they react negatively. Again this approach isnt for everyone, so I guess I'll take an economical approach (seeing as its being shoved down my throat right now) if the amount of healing you will gain is greater than the amount of stress you will have to endure in telling them, I say tell them. So in closing, I think you should tell them, but ultimately the decesion is still up to you