Adult swim, is just that, for adults. You never know what they are going to have on there. I used to let my son watch Family Guy with me as he was going to sleep when he was, like 2 years old and had no idea what they were talking about. However, there came a day when he reached a certain age (don't remember exactly how old, but not that old) when I said to myself, he is getting too old to be watching this, he's going to start asking questions about what they're talking about or repeating certain words. So, I quit watching it and now will only watch after he has gone to bed. Family Guy is really the only show I have ever watched on Cartoon Network, most of the others I find asinine.
It was kinda like watching a rated R movie when he was a baby, he had no idea what was going on. But as a responsible parent, there came a day when you realize, he can pick up on certain words, actions, etc. That was the day I had to start picking and choosing what was appropriate to have on when he was up and what was not.
Last night Grown Ups was on, and I sat down to watch it. He curled up beside me, he's almost 9 now. When the 4 year old ran up to the mom to nurse, I almost changed the channel. But, decided not to make a big deal of it. He's an only child and has never been around a nursing baby. Later on in the movie, he said, "Mommy, that boy is like a baby kitten and his mom is like the momma cat." I said, "You are right son" and that was all that was said about it.