I should have annotated that. "It's in a man's nature," which I translated from 男の性 (otoko no saga, more or less the same meaning). It means that if a man (or a boy, in this case) is curious or enticed about/by something, they'll more than likely try it. The phrase refers to natural drives, being lead by your desires. Those "pervy stools" (スケベ椅子, sukebe isu) in this case.
If you meant the sentence works better without "in a" then yeah I guess you might be right.
Basically the same thing.I thought it meant that men are pervs and want to try pervy things.