Elizabeth,
Before Five In A Row was written by Christians. There is a separate Bible lesson to go along with each book. You obviously don't have to do that lesson, or any other lesson, it's up to you. I don't think that, besides the Bible lesson, you would have anything to worry about, or any lesson to omit. There are tons of little lessons or activities to go with each book. The lessons focus on exploring our world(ie. science, art, language) and being imaginative, kind, loving, sharing, etc...
I think that most parents, regardless of religion, want to teach their children to treat others with love and kindness. Before Five In A Row does this. After all of this rambling I think that you would be ok. Maybe someone else will be able to add more. I think that it is a great program and I wish you luck in whatever you choose.
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