This actually happened at UCD (University College Dublin)
in October of last year. Thought you would find it educational.
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, you're saying there is a lot of glucose,
as in sugar in male semen?"

"That's correct", responded the professor, going on to add
statistical info. 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's face turned bright red, and as she realised
exactly what she had inadvertently said (or rather implied),
she picked up her books without a word and walked out of
class... and never returned.

However, as she was going out the door, the Professor's reply
was 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 the back of your throat."

Hmmm...