A man and a woman meet in the elevator of a high-rise office building.



The woman asks for the 10th floor and tells the man she is going to donate blood.



She says that she's able to donate once a month and that she earns $10 each time.



The man laughs and says that he's going to the 20th floor to donate his sperm.



He tells her that he is able to donate every day during his lunch hour and that he earns $20 every day.



The next day the same man and same woman find themselves in the same elevator.



The man says "Hey, are you going to donate blood again so soon?"



The woman shakes her head from side to side and mumbles "Muh muh".