True Story
 

This happened at a major Australian University, during a biology lecture. A professor was discussing the high glucose levels found
in semen. A young woman raised her hand and asked, "If I understand you correctly, you are saying there is as much glucose in male semen as in sugar? "The professor responded, "Yes, that's correct", adding some statistical data to his lecture.
Raising her hand again, the girl 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 realised exactly what she had inadvertently said, she picked up her books, and without another word, walked out of the class - and never returned. However, as she was heading for 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