Kevin - does he have a dick?
In the scene where Kevin is on the other side of the swimming hole he appears to be "neutered". Was he wearing skin-colour underwear, was it cold weather or was he hiding it between his legs?
He was intentionally hiding it.
shareI agree - the way he was acting (playing a fool) also back this up...
Also if he did not have a penis it would have made the fact that Jack found him in bed with his wife (Evelyn) a bit strange. This is only mentioned in the dialogue between Joe and his sister when Joe is told that Evelyn died.