You believed them?

I had a very interesting conversation with my son the other night and it started with this question:
Landen: "How do you know McKaylee is a girl?". Thinking I could brush off this possibly birds-and-the-bee's question, I went with the silliest answer first, "What do you mean, her name is McKaylee, that's how I know". Not much to my surprise, this did not work. Landen: "No, but how do you know she's a girl?". Looking down at her tiny bald head and her barely-there eyelashes, it occurred to me that because of the chemotherapy she's been through, she's lost all her physical markers as a female. Well, obviously not all of them, but she doesn't have pretty brown hair swept back into a pink bow or her beautifully long eyelashes that made every noticing woman jealous. Trying to be sensitive to the situation, I approached at a different angle. "Well, honey, I know that she doesn't have hair anymore, or her eyelashes, but she's still a little girl. Losing your hair doesn't change who you are on the inside.". Completely content with my answer, I could feel a smile face creeping across my face as I had put my son's deepest questions to rest...and then...
 Landen: "No, Mommy, I mean when she was in your tummy, how did you know she was a girl?". Suddenly feeling ridiculous for my former responses, I blushed and offered up the simplest of explanations, "They took a picture of her in my tummy and the doctors told me she was a girl.". Landen squinted his eyes in what appeared to be complete disgust, "And you believed them??". I have no words for this response, just a smile for my wonderfully curious and always cynical five year old son.