Guy's Behavior

Why do men like farts?

Okay so a (female) friend of mine asked me why men think farts are so funny. I began typing: "Well in the early days of mankind, men used to fart because" And then I stopped. I couldn't think of any reason why it's evolutionarily beneficial to promote farting amongst men. Why do men like farts and - perhaps more imporant for answering this question - why don't women?

(The rest is just my line of reasoning. If you've stuck this far I suppose you're interested enough to read to the end, but if you've already got an idea for the answer you can just skip the rest.)

It is clearly not beneficial for the posterity, otherwise it would be used to attract potential mates, but women don't like it. That might lead you to conclude that farting is a disbeneficial trait for a man's posterity, but why do men find it then funny to fart amongst one another, and why did evolution not get rid of it?
Could it be a way to separate men and women? But why would that be useful?
What could farting signify? Is it a sign of properly functioning intestines, or of overall good health? But then, again, if men like it because it's a sign of good health, why don't women find it funny?

I know many people will consider this a stupid question but the scientist in me is curious and frustrated because I can't think of any reason. Let me know what you think. Again, just to clarify, I believe that all behaviours and social constructs have or used to have an evolutionary purpose, and I'm therefore looking for an explanation based in science as well.
Why do men like farts?
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