Every once in a while, a reddit thread will pop up on one of the subs I frequent with a question like this:
“I don’t believe the religion anymore, but my sister just asked me to be godfather to my new nephew. What should I do? Should I lie about believing and go along with it because I do plan to be a special person in the child’s life anyway, or should I tell the parents I no longer believe in god and say I therefore can’t be a godfather?”
Obviously, there are variations; sometimes, the person with the new baby is aware the poster does not believe but has asked them to fill that role anyway.
Invariably, someone will say to be honest with the new parent and tell them you are an atheist and are uncomfortable being a godparent, and that is certainly good advice. If the parents only want “special adult role model for my child” and not necessarily the religious baggage of the title, there is really no ethical problem with being that person regardless of what you do or don’t believe.
My angle, however, is a little different.
In Catholicism, a godparent vows as part of the baptismal ceremony to help raise the child as a good Catholic. In my conversations with other ex-Catholics, I’ve seen that many of us are not on very good terms with the Catholic Church and are certainly unwilling to help put a child through what we went through. I personally could not honestly promise that I could do anything to help raise a child in that tradition. To me, that would seem unethical, akin to promising to lie to a child about monsters under his bed when there are none.
I thought I would have more to say, but that is about it. Every situation is different, and only you are close enough to your situation to know all the variables of whether you should be completely honest. In general, however, it is certainly unfair to the new parents to promise to help them raise a godly child when you are an atheist incapable of fulfilling that role.
The Complete History of the Universe: A Personal Journey 