Cuddy's desire to have a child was an in-and-out story arc during Season 3 and, IIRC, part of Season 2 (towards the end.)
The arc was all-but dropped by the time Season 3 ended and Season 4 began.
House going through vicodin withdrawal and going off on Cuddy about how bad of a mother she'd be was one of the coldest things I've EVER seen on TV.
Yeah, indeed it was. It's what makes House such an interesting show and character.
I mean our "hero" is a grade-a asshole!