Honestly? Your parents will either be disappointed or not, and no matter how you tell them they will still feel that way. BUT! If they are disappointed, with time they will grow to understand and accept it. The thing about them growing to accept it is the sooner you tell them, the sooner they will be able to start trying to understand and accept you. The longer you wait, the harder it will get. Its definitely not going to get easier by waiting. Of course, there are a few things you can do to lessen the blow so to speak. One is obvious, dont tell them when they have too much else on there plate. If you tell them when they are stressed then that could end badly. Two would be to write them a letter or e-mail when you come out and start it off telling them how much you love them and other such things to re-enforce that its not a big deal. Soften the blow with lots of fluffy emotional goop You could also give them PFLAG material, other books, or videos to watch that help them on the path to understanding you. But, again, there is no way to stop a parent in being disappointed when they hear the news that very first time. You just have to prepare yourself for the worst and hope for the best.
Thirded. Greg has a way of beating me to the punch when it comes to giving advice! Some parents will be disappointed if you come out to them, and the way you come out won't change that. But that doesn't necessarily mean they'll be disappointed in you. Maybe they'd be disappointed because they'd think it'll mean you won't have kids, when it's more than possible that you can and will (assuming you want to). Maybe they'd be disappointed because they'd think life will be a lot harder for you than it would be if you were straight, which can be true, but that doesn't mean that you can't have a great life. I'd suggest you read through the "Coming Out Stories" section, have a look at how other people have come out and how their parents reacted, try to figure out some of the most likely questions your parents will ask, and think about how to answer them.
fact is parents will always be a bit dissapointed and worried maybe upset the fact no wedding grandkids those are the sorts of things then they think of your social and health ... but they love you and want you to be happy i agree with greggers aswell its all good advice
come out to them. My parents foudn out from a stupid student at my high school. Im still not sure hwo they are dealing with it. Its better you come out yourself then someone else coming out for you. Its only when u feel ready. It makes life alot easier cause it means no more hiding. Over time people accept us.
Don't assume that you being gay is going to be a disappointment to your parents. It is simply a part of who you are, and they love who you are. They'll need some time to get used to the idea, just like you did. So don't expect them to be totally cool with it right away. But to assume that you will disappoint them will really drag YOU down.
This mostly worked well for me, but be forewarned: if your mother is a very emotional type, you may be fending off her clingy desperate attempts to reassure you of her love for a very long while.