I don't believe that there's a god, let alone a god who had a son born in a manger to a virgin, but I really hate to influence children (including my own) by stating that aloud. So far, I don't think that any of my children are Christian, although that could change and I wouldn't care at all if it did. Belief systems, in my opinion, are personal. I don't want to sway you from yours and I sure don't want you to sway me from mine.
Christmas and the gift-giving tradition born out of it, however, presents a dilemma for non-believers who don't want to engage in the hypocrisy associated with so many Christians. Children are too new to the world to deal with belief/non-belief systems out of the norm, and as No. 1 has reminded me too many times to count as I asked her how she always seemed to end up with Christian boyfriends, "The US is 85% Christian".
So, when my kids were little way back in the day, I pretended that there was a Santa Claus. BIG MISTAKE! No. 1 would say things like, "Why would Santa think I would want something like this?"
As the years went by, I think the kids just enjoyed getting gifts and the fun associated with opening the gifts even if the gifts weren't what they wanted.
Somewhere along the line, I stopped pretending. The kids were grown and aware of my non-belief, Em's a non-believer as well, and there were/are other venues for everyone. Then came Astrid.
I fancy myself her teacher in these early preschool years, although No. 1 and husband are doing an excellent job at ensuring appropriate development, as well. It's my intent to teach her bible stories along with Aesop's fables and Greek/Roman mythologies. She's a bit young for that now, IMO, but is totally smitten with Frosty the Snowman. We watch a 3-minute Frosty video every visit THREE times. So far, she's not asked about Santa (who appears at the end of the video with Frosty), but I suspect I'll suggest to her that Santa is "the spirit of Christmas" if (and ONLY if) it comes up.