Jason found a "Married to the Kelly's" discussion forum online here. Most of the posts are pretty positive, but there's one that says this:

"In the one scene where Susan is trying to convince Tom to go up to Louis's room, she says something to the effect that he can't help being odd since he grew up with four sisters. Is that right? If so, did they change it after the pilot episode or are there two phantom sisters that we'll only hear about and maybe see in another episode?"

Lisa, I think you should head over there and clear things up for them.

-Jon