Wikipedia’s entry on vulva includes the following explanation: "In common speech, the term "vagina" is often used improperly to refer to the vulva or female genitals generally, even though strictly speaking the vagina is a specific internal structure and the vulva is the exterior genitalia only. Calling the vulva the vagina is akin to calling the mouth the throat."
The female genitals have many colloquial names, and parents find different names acceptable to teach their children. Some stick with the timeless classic "pee pee." Others go with the anatomically inaccurate (when it comes to the parts involved in diaper changes, at least, unless I’ve been doing it wrong) "vagina." M knew someone once whose kid called it a yoni. M has encouraged Lennie to call hers a vulva. It’s accurate, not offensive (we could have gone with snatch or another vulgar colloquialism, after all), and not terribly difficult for a 20-month-old (as of yesterday) to approximate in speech. Lennie’s got it pretty well down. Now, when she reaches down there with both hands during a diaper change and tugs (and I mean tugs), she can call it more or less by its proper name. "Bulba," she says.
So she’s got the vocabulary. All she needs now is to apply it correctly. Sometimes when I step out of the shower (let me pause for a minute and say that if you’re choking over the fact that my 20-month-old daughter sees me naked sometimes, just grow up and get over it; it’s not like nudity is bad or in any way unnatural, and it’s sure not as if I’m doing a pole dance for her or anything), she’ll point to my butt and say "Daddy booty" (why we’ve chosen a colloquial term for that muscle and have insisted on something more clinical for the old naughty bits I’m not sure). Then she’ll sometimes point to my junk and say "Daddy bulba."
So. Yes. I seem to have a vulva. I’m a little hesitant to teach her that what I have is called penis because the same people shocked that my young daughter has in fact seen my penis as I’ve stepped out of the shower will no doubt call child protective services if they hear of her saying "Daddy penis." Daddy bulba will do for now. As her pronunciation improves a little, I can perhaps feel somewhat safe in the likelihood that people who may hear her speaking for whatever reason about my genitals will think she’s in fact talking about my durable German car.