Religion vs. Culture or Beliefs vs. Lineage

This is a general secular, sociological question.

So, the question is, can a cultural Christian throw his faith and beliefs away once he finds out he has a Jewish family line? I understand the cultural paths of both Jewish and Christian, but I'm wondering what it says about faith and what you believe in.

So I have two questions: (1) Does one go to church/synagogue because it's expected of him in the community/society?

and (2) Does one abandon and/or embrace what they've always believed in order to embrace another faith because of genetic material?

This discussion is NOT to let me know which one is better or why. Reiterating: This is a general secular, sociological question. That is all.