I just bought my tickets to Family Day at "Xanadu: the Broadway Musical." My partner and I saw it a few months ago and we have been excited to take our two kids (one boy, one girl 8 & 7). It's a lot of fun for the whole family. It's campy, witty, and well-performed so that the adults are entertained, but it's not dirty, and there's enough romance and roller skates that kids will love it to. Haha!
Anyway, there is a Family Day at Xanadu in August.
http://xanaduonbroadway.com/family/
The Philadelphia Gay and Lesbian Theatre Festival has produced James Still's Iron Kisses. A play which focuses on a rich man's nuclear family with a gay twist. The son, Billy, is gay and getting married to his lover, Michael, in San Francisco.
The Philadelphia Inquirer gives the show gets a so-so review with a nod to set design.