Asexuality: Word of God may have said that Clyde is supposed to be impotent, but the movie never states so and his entire sexual behaviour comes across much more like this. (For example: Why doesn't he try to please the very frustrated Bonnie in other ways than penetrative sex, if he is sexually attracted to her but just suffers from ED? How come his supposed chronic physical problem just spontaneously resolves itself in the end without comment? Why does he act so very awkward when they first try to have sex, and doesn't give himself more than a few seconds time to react to Bonnie's touch before giving up?) Considering this was made in the 60s and the general expectation of A Man Is Always Eager, it's entirely possible that the writer based Clyde's behaviour on somebody who actually was asexual, but who he thought must be impotent. Or that Word of God actually meant "unwilling to have sex" but didn't have a better word for it, in the same way that asexual women were called "frigid".
Clyde: I might as well tell you right off: I ain’t much of a lover boy. That don’t mean nothing personal about you. I mean… I… I never saw no percentage in it.