I chose both "Protestant/Other Christian" and "Atheist/Agnostic". My mother was raised Southern Baptist, but abandoned it before I was born. My father was raised...Lutheran, I believe, but also abandoned it, and Christianity itself, long before I was born.
I think that my parents made a deal before they had children, which was that they wouldn't raise their children in any particular religion, but, I could start going to church when I turned 13, if that was what I wanted.
So, I really wasn't raised anything at all. My family celebrated Christian holidays (Christmas, Easter, etc.) without any religious aspects to them at all. Christmas was all about Santa, Easter was all about the Easter Bunny, etc.
However, I was raised to thoroughly believe in, and trust, science. The Natural History Museum was practically a second home for me.
Right now, I would classify myself as an agnostic.