Yes, and you'd be amazed at how many otherwise reasonably intelligent and college educated people believe it because their professors have insisted it was true. Television shows that feature waifs beating up brutes also don't help. They don't even seem to get it when I point out why athletes in combat sports and other strength-related sports are separated into weight categories for a reason.
If you really want to tweak their melons tell them that men are smarter than women on average also.
It is completely 100% true, but once you correct for size - women are smarter. (but don't tell them that!)
I am 6'2” and 200 lbs and score embarrassingly high on tests. Not as many 6'2” and 200 lb women with equivalent sized heads out there.
And yes, boys and girls- size does matter.