The Brady Bunch, Season 3

(Carol is looking at Bobby stretching himself outside)

Mike:
What are you looking at?

Carol:
Bobby. You think it's good for him to stretch himself like that?

Mike:
Never hurt Tarzan.

Carol:
Oh, think what it did to Jane.

Mike:
Honey, he's not gonna hurt himself.

Carol:
He's at it all the time.

Mike:
So?

Carol:
Well, if his arms stretch and his legs don't, he may grow up to look like Cheetah. (both laugh)