The Birds and The Bees, already?

Today, I was left at home with my niece for about an hour. We started working on a puzzle and she initiated a conversation about marriage; my niece is 5 years old. At some point she asks, do you have to kiss a boy in order to have kids? I froze for a second. My niece and I always have conversations, she is very mature for her age and has already asked the basic questions about God, family, friends, death, etc. As an aunt, I have no problem with talking to my niece about sex......but at 5 years old, it's too soon for her to even grasp that subject. I laugh, as her bright eyes look at me, eager for an answer. I fear that the next question will be, how do you make children? I develop an idea to change the subject, just in case that second question comes, and answer her first with a "No". Her beautiful eyes look up, and I can see that she is processing that information to what her idea of marriage is. She keeps working on the puzzle; I'm safe for now.