This one actually happened at Harvard University in October last year.

In a biology class, the professor was discussing the high glucose levels found in semen. A young female (freshman), raised her hand and asked, "If I understand what you are saying, there is a lot of glucose in male semen, as in sugar?" "That's correct." responded the professor, going on to add much statistical data. Raising her hand again, the sweet young thing asked, "Then why doesn't it taste sweet?".

After a stunned silence, the whole class burst out laughing, the poor girl turned bright red and as she realized exactly what she had inadvertently said(or rather implied), she picked up her books without a word and walked out of the class, and never returned.

However , as she was going out of the door, the professor's reply was a classic. Totally straight- faced, he answered her question, "It doesn't taste sweet because the taste-buds for sweetness are on the tip of your tongue and not in the back of your throat!