A man and a woman were waiting at the hospital donation center.
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 center.
Man: Oh, hi there! Here to donate blood again?
Woman: [shaking her head with mouth closed] Unh unh.