A man and a woman were waiting at the hospital donation centre.
Man: "What are you doing here today?"
Woman: "Oh, I`m here to donate some blood. They`re going to give me $5 for it."
Man: "Hmm, that`s interesting. I`m here to donate sperm, myself. But they pay me $25."
The woman looked thoughtful for a moment and they chatted some more before going their separate ways.
Several months later, the same man and woman meet again in the donation centre.
Man: "Oh, hi there! Here to donate blood again?"
Woman: [shaking her head with mouth closed] "Unh unh."