Is this illegal in North Carolina?

A friend of mine flipped out when the heard I sleep next to my father. When I'm at his house, there's only one bed to sleep in. We sleep with different blankets, and there is no "bad" things happening. They said it was illegal and immoral. And to me, I don't think it matters. I'm sixteen and he is my father. I don't see the problem... but is this illegal?