Two little boys, nine and four, entered a store
Picked up a box of tampons and went to cashier.
He asked “Is this for your mom?” Nine year old
Said “No”. He then asked “Is it for your sister?”
Nine year old again said “No”. Curious by now,
Cashier asked “Who are they for?”. Nine year
Old said: “For my little brother. For they say on
TV, if you wear one of these, you can swim or
Ride a bike and my little brother can’t do either.”

http://kvakutty.sulekha.com/blog/post/2008/10/who-are-they-for-humor.htm