You're in a tough position trying to counteract what your step-daughter may be getting at her mother's house, especially since you probably don't know everything she's being exposed to. She is lucky to have you in her life. I don't know if you are a Christian or not, but if so, check out the "God's Design for Sex Series." I believe you can get it through christianbooks.com. It's a very non-threatening way to introduce this issue to young children in storybook fashion, and could be a good alternative to what she may be receiving elsewhere. If you're not Christian, just disregard this, and keep doing what you're doing anyway. Even though you can't tell how much is sinking in, I'm sure some of it is. God bless you.