An article on TV families and whether they get along in real life includes Seinfeld - technically not a family, but the closest thing to one in the opinion of the writer:
"Yeah, we know, not technically a family. This is a fairly short list so the rules are being bent. Deal with it. And, besides, this characters, for all intents and purposes, were a family. Sure, Jerry Seinfeld seemed to revel a little too much in the supposed "Seinfeld curse" that befell his fellow cast members -- that is, until Julia Louis-Dreyfus won a post 'Seinfeld' Emmy and Seinfeld won something called 'The Marriage Ref.' Regardless, Jerry Seinfeld was the only human alive that rushed to the defense of Michael Richards after spouting racial slurs at a comedy club. And most notably, the cast principals were still on good enough terms to film a mock reunion show for Larry David's 'Curb Your Enthusiasm.'"