There's some evidence Chase has a half-sister - in...crap, I'm not sure, I think "Fools for Love?"...after Chase thinks something genetic might be a coincidence, House says "is it a coincidence your sister has great hair?" So, probably, though of course there's always a possibility House was being metaphorical, I guess.
And, hee, I'm pleased we know the most about Wilson of any non-House character, I have to admit. I posted something about that a few days ago, coincidentally,
here in the Wilson thread. I said, basically, that you can divide the supporting characters into two categories, if you're so inclined: ones whose family/parents we know about (Foreman and Chase, and now Kutner too), and ones whose romantic lives we know something about (Cameron, Cuddy and most of all Wilson).
And, can I indulge myself in a mildly tinhat-ish overthought theory? Foreman and Chase, and probably eventually Kutner, are positioned as surrogate (adopted) children of House, so it makes sense that we know about their upbringing. Cuddy and Cameron are canonically love interests for House, so it makes sense that we know about their romantic pasts. This, to my mind puts Wilson more strongly in the love interest category since we know much much more about his romantic life than we do about his parents. (Yes, a sample size of 5-6 is probably too small to draw any concrete conclusions, but I said this was me being self-indulgent, right? *g*)
So. If it follows that there are 3 love interests, let's look at how much we know about their families: Wilson most, Cam in the middle, and Cuddy the least. Cuddy, we literally know almost nothing about aside from her career, including her romantic/sexual past outside of House. With Wilson, we not only know Wilson's family's basic composition but a little hint of their dynamics if they could have a missing relative they never mention.
So, what (admittedly biased) conclusion does this lead to? Cuddy seems very much in the substitute mom role, based on what we and House know about her - it makes sense that arrested adolescent House has little interest in her life before and outside him. And Wilson, who we know most about? The spouse. That's how I'd describe the love interest whose family one knows most about, anyway.
...there are probably numerous holes to be poked in this, of course, but I love my theory, so, yeah.
And, wow, did I really type something that long? Yes, yes I did. I must really want to avoid doing work today...
Edited by Poeia to fix link and remove stray tag.