A quote from Carlin...
"There are no such thing as dirty words... Just dirty thoughts."
I was brought up differently from the masses. I was allow to use the "dirty" words as soon as I learned them (mainly from my father), started around age 6.
The only thing was that mother sat down and explained all the dirty words, even got out the dictionary (finding a dictionary in the 70's with the words was a pain) and made me look up the definitions. The rule was that I could use them as long as I didn't direct the words at a person. Inanimate objects, or myself was allowed, but to throw them at a person was forbiden. The idea was that the words are valid words in the english language, and that they could be used.
One thing that still sticks in my memory, was the psychology book she brought out that explained what happens when someone uses the "dirty" words. If you notice, the words are mainly single syllables, that require the lower diaphragm to use. The book explained that being single syllables, and lower diaphragm, they relieve stress. The book also explained that the same thing is done in other languages. I thought that was cool.
But I do understand that certain people in society do not like those words, so by being an understanding person, I [i]try[/i] to keep the usage to a minimum (doesn't always work).