Are you friends with them on facebook? Make your religious preference “agnostic.” ;)
I guess that’s how my parents officially “found out” I was an atheist.
I think any belief in god I had was gone by age 13 or 14. (And I had just made my Confirmation the year before!) I never said anything about it then; I continued going to mass with my family and attending Catholic school. However, I stopped receiving communion at mass around age 16. I guess that was my parents’ first clue. My parents had a problem with it and brought it up with me, but I probably just said something like, “I don’t feel comfortable receiving communion because I do not feel connected with ‘jesus’/catholicism.”
When I went away to college, I think it was pretty evident that I wasn’t going to mass…
My parents were fine with this and we started to develop a really nice relationship with each other when we were no longer living together (constant arguments when I lived with them!). We sometimes had discussions, in which I was candid about my disagreement with many Catholic beliefs. My parents did not have much of an issue with this because they disagree with many elements of Catholicism as well. But in the conversations, it was always apparent that I disagreed with a lot more than they did…
I am now 23, and when my mom got facebook back in November, we became facebook friends, and I’m sure she saw it because she made specific comments and laughed about many elements of my profile. However, she didn’t say anything about it.
She didn’t say anything about it until I was visiting her a few months later and we had a few cocktails together and got into a discussion about religion. She started to cry and said how much seeing the word “atheist” under my religious preference on my facebook profile absolutely breaks her heart and how she feels it is her biggest failure… to have raised a daughter who became an atheist.
In response, I told her that she should feel successful for raising a healthy, independent mind. She always told me to think for myself, investigate ideas, analyze my own thought processes, learn, and come to my own conclusions.
I feel much happier not pretending to be something I am not around my parents (and I also generally feel uncomfortable when people think I am religious). However, my mother is very sad about it.
Take from my experience what you like.