Do boys have a natural inclination to find bodily functions and terminology amusing?

I sometimes waste a lot of time playing puzzle games on the computer. One of the games I have been trying in vain to beat is called Hexic. It involves moving tiles in groups of three to make some of the tiles disappear, and to surround one color of tile with 6 tiles of another color to create special tiles. At higher levels of the game there are periodic bombs that will come on, and you only have a certain number of moves to remove the bomb by matching it to two other tiles that have the same color as the bomb in order to make it disappear.
The boys enjoy watching for bombs when I am playing, and they like to predict when one will appear. The other day #4 and #5 were watching me and waiting for a bomb to come on the screen. #4 was trying to predict and #5 copied him, but mispronounced bomb as bum, after which he started to giggle and said, "I said bum." He thought it was the funniest thing.
I have also noticed through the last ten years of parenthood that my boys find any kind of bodily noise to be highly amusing. I can't say that they would giggle about it as a tiny baby, but certainly they learned very young to be amused at belches, and toots as they call them. When my 8 year old found out what breaking wind meant he laughed almost hysterically about it.
Since I only have boys I am wondering if this spans all of childhood or if its primarily a boy thing. Maybe there is some truth to that old adage when a newborn baby smiles, that "Its just gas."