Fair-haired women performed psychometric intelligence tests more slowly after reading dumb blonde jokes, German psychologists have found in recent research.
Well after all, that's the purpose of the jokes isn't it, to keep them brow-beaten and downtrodden?

Actually I'm related to a couple of these blonds who seem to enjoy the jokes, within limits

.
Comfort the afflicted and afflict the comfortable.
--- William Sloan Coffin (and many others)