How do I tell my niece about my beliefs?

[ej2539]

I don't think she's ever heard of the stork. When she asked my sister where babies came from and how they get there, my sister was very frank and honest in telling her how it happens. But she does believe in the easter bunny. She already understands that different people believe different things - she has friends who are Jewish, Muslim, Catholic, etc. - and she understands that her parents like Obama but her grandparents like McCain. What I'm worried about is the inevitable "why" that follows when I tell her I don't believe. She is all about asking why. When she asked me why my tummy was bigger than my sister's, I told her honestly it was partly because people are built differently (tall, short, thin, fat) and partly because I eat more than her mom does. That was easy. But I'm worried that my reasons for not believing in god will come off as more condescending or confusing.