I didn't grow up in a religious household, but it was probably Christian. The thing is, my fathers side is mostly apathetic towards religion. Politics and religion on my fathers side was almost never talked about. (Which was really nice) My immediate family identified with my fathers side the most. My mothers side was far more religious and kinda rubbed me wrong as a kid. Mothers side would sometimes say grace during dinner and attend church. My fathers side was never like that at all.
When things would get tough like people dying or whatever, then sometimes they would sort of clasp to their god believing roots, but generally it was never like that. So, I grew up in a household where I didn't have to be constantly brainwashed. (Not like it would work anyway. I got teased by so many people, especially family, that my critical thinking skills shot through the roof. You learn quick to NOT believe anything ANYONE says.)
I remember going to church a few times with my immediate family. Sometimes with the mothers side of the family that lived near us. I hated church because it was boring as fuck and my mind was just like, "why are we here for this?" At the time I didn't think people really believed the things that were being preached. I thought they just went there to listen to batshit insanity, and so it made no sense to me why anyone would listen to this.
So, one day when my mom was out on the couch watching TV I just came out there and was like, "Hey mom. I have something to tell yah." "Yes honey?" "So, I'm like... an atheist..." "Oh. I figured that might happen. You know, with you and science and all." *Huge wave of relief.*
My mom and dad were fine with it. They really don't care. They are so apathetic towards politics and religion.

They're more concerned over things that matter, like family.