1, 2, 3 or 4

Two teenaged brothers were arguing with each other very strongly. The issue was who knows better and more about the sex.

The elder brother of seventeen gives a challenge to his fourteen year old younger brother.
He says "I will ask you a basic question about sex and if you reply it correctly, then only I will admit that you know better and more about sex than

me."

“O.K. Done. Please ask." said the younger of fourteen.

Elder brother asks his younger brother, “Tell me, how many testicles we have, taken both of us together?”

Younger replies instantly, “It’s so easy, Four”.

The elder one says, “Wrong. I have only one.”

Younger one replies, “But I have three, what about that.”