they weren't raised as brother and sister and had no idea that they were related at all

I do see what you mean. I've watched that episode a few times now.

at the end we see her throwing away a negative pregnancy test

That was sad. I want to hold her and stroke her hair.
...Oka-y. I just made a seamless transition from "cruisin'" to "deeply affectionate" just then. Odd.

Which leads to less Cuddy for us

The mere mention of that sends waves of fear through my stomach.

Cameron/Cuddy sex scene joke?

I don't know! It's a mystery. Haha, how awesome would it be if all of a sudden in one episode one of the characters was walking down a hall and they turned a corner and Cameron and Cuddy were making out against the wall? Hee. That's how I would do it.
Hmm... actually, probably not. That's just the first mental image that popped into my head.