None of my sponsors have been secular. I asked my first sponsor to work with me because we were both young and there weren't that many young people around at the time. My next two sponsors, the relationship was there before it became anything formal. Right now, I'm in what is more or less a co-sponsor relationship with a friend who's a Pagan.
I'm sponsoring some guys who are most definitely not secular. It's not my place to tell them who or what is their HP. The only HP I need to be concerned with is mine. Religion almost never comes up - it's an outside issue.
-allan