A couple gets a divorce and are in court fighting for the custody of the children. The judge asks each of them to defend their reasoning for their right to sole custody.
The woman begins, "The children are mine! I carried them for 9 months in MY body and spent hours in labor birthing them! He didn't really do anything!" The judge nods thoughtfully, recognizing the validity of her reasoning, and asks for the man's defense.
The man thinks for a minute and replies, "Your honor, if you put a dollar into a drink machine and out pops a coke, who does that coke belong to, you or the machine?"