In a Harvard biology class, the professor was
discussing the high glucose levels found in semen,
which gives the sperm all the energy for their journey.

A female freshman raised her hand and asked, "If I
understand,you're saying that there is a lot of
glucose, as in sugar, in semen?"
That's correct," responded the professor, going on
to add statistical info.

Raising her hand again, she 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 realized exactly what she had inadvertently
said (or rather implied), she picked up her books
without a word and walked out of class.

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 others are
closer to the back of your throat. Have a good day."