The boy on a nude beach.

Two parents take their son on vacation and go to a nude beach. The
father goes for a walk on the beach and the son goes and plays in
the water. He comes running up to his mom and says, “Mommy, I saw
ladies with boobies a lot bigger than yours!”

The mom says “the bigger they are, the dumber they are.” So he goes
back to play. Several minutes later he comes running back and says,
“Mommy, I saw men with dingers a lot bigger than Daddy’s!”

Mom says, “the bigger they are, the dumber they are.” So he goes
back to play. Several minutes later he comes running back and says,
“Mommy, I just saw Daddy talking to the dumbest lady I ever saw and
the more and more he talked, the dumber and dumber he got!”