You can go on one of the many gaydays.com websites to find the "official" schedule -- it will tell you which parks the Gay Days organizers are stressing on which days. Then, simply avoid the featured park. (This is a crowd-fighting strategy, not necessarily an "avoiding gays" strategy, as many of the Gay Days folks do this too, to try and steer clear of crowds.)
I will say that yes ... you might see some outrageous costuming. I will always remember the day I saw the 6-foot man in 6" heels and a red vinyl one-piece catsuit go through the turnstiles. (He was in First Aid about two hours later, being peeled out of his vinyl suit and given fluids for dehydration -- why he chose vinyl in Florida in June, I'll never know.) There are also drag queens dressed as princesses (but never inside the park, as Disney will not let adults in costume enter the park, no matter what day it is -- those folks are asked to change and not admitted until they are "de-costumed"). But folks like this are the rare exception, not the rule.
As one poster upthread mentioned, you're more likely to see heterosexual couples making out in lines and on attractions than you are to see overt gay PDA. Of course, as is true for any large group -- from cheerleaders to gospel choirs to family reunions -- having a large number of folks on a ride or attraction with you might cause some annoyance (chanting, singing along with attraction music, photo-taking, etc.). So again ... try to avoid the featured park.
The thing to remember is that there are gay people, gay couples and gay families at WDW every single day of the year. There are a large number of gay Cast Members, and this includes managers and VPs and even characters. If you're not worried about your kids on any other WDW visit, then you don't need to be concerned for them during Gay Days.
What is it with teens, night time and a pool jeez. 
