Can Christians sin? I think so. In fact, I think some Christians may not do a very good job in refraining from sinning. In fact, I think that is why many Christians believe Jesus came to Earth...to set them free of their sins.
Why am I pondering this question, anyways? Because I actually chose to put references to God in my novel. And my novel is about a relatively average teenage girl, and her family, who sin, and also believe in God. And in things that go bump in the night.
Are you scared? Does it make you angry? Does it make you feel normal?