Well, EFMom, here's what I think about what you said. Feel free to disagree!
First off, I don't think "shameful" is the appropriate word. The fact is, private parts, whether male or female, are not noses or knees. There is a difference, in the way we treat these body parts (ie keeping them covered in most situations, refraining from touching them in public, not allowing others to look at or touch them without a good reason) and in the way society treats these body parts. I think dealing with them in a different way (whether or not that includes "code" words) transmits the message that they are different. Not bad, but a special part that is treated in a special way.
Secondly, if the nose or the knee was encumbered with a medical-sounding name, you might well use an alternative word! I still say belly button, not because I think it is a shameful body part, but because navel has always sounded too technical and kind of ugly. ("I want to get my navel pierced." Ugh.) If the only official word we had to describe fingers was "phalanges," I'm sure there would be a kid-friendly term in use for them as well. I'll wager you use "funny bone" instead of "ulnar nerve" yourself!
I could go on and on. Not exactly a body part, but when potty training, do you say, "Can you urinate in the potty?" "Do you need to defecate?" "Say bye-bye to the fecal matter!" Maybe you do. I don't think that's for me; I prefer the cutesy words!
Lastly, if I feel goofy saying "vulva," I'm sure dd will pick up on that. Wouldn't it be better to find a term I can say without feeling weird about it? Of course when we are discussing a serious subject like sexual contact or reproduction, the official words would be used.
SO, what do you think? I'm glad someone from the "correct-names only" crowd finally posted b/c I'd like to hash some of these ideas out and make sure I feel comfortable with the decision I do make.