Do you think being religious comes from families that heavily believe in it? If your family was not religious would you still be?
I do not think that being religious comes from families that believe heavily in it. (Note following, then full answer)
[NOTE: I am personally defining "religious" more as faith-based instead of the actual definition of "religious" which means to follow all the rules with complete and utter precision. The literal definition of "religious" (which I do not abide by) implies that the rules are of the highest regard, while my interpretation of what I think you are trying to get across is more about faith and love for the object of your faith. I also am assuming that you are talking about Christianity, since that is what I know and I am public about it. "Religion", which is literally just all about rules and regulations, does not line up with Christianity, where we follow "the spirit of the Law" and not "the letter of the Law", allowing the Holy Spirit to work through us and in us to empower us to refrain from sin.]
I know plenty of people who come from "non-religious" families who are strong in faith and who are leaders among those in the church. One of my RAs this year is an example - he was the first in his household to come to faith in Jesus, and I know few who have faith like his. I do think that having a "religious" family can contribute to the faith of the children, but it is very common for kids to walk away from the faith in their teen or college years when the faith is approached in terms of rules and regulations (the literal definition of religion). It goes either way. I do not think we can definitively say, unless you look at a family who has a strong belief in Christ and who follows "the spirit of the Law". In that case, I think you would see a higher probability of faith in the children because they will have seen the truth of it.
In the literal definition of "religious", however, when it comes to other faiths such as Hinduism and Islam, I would say that family following of a certain religion does play a part, especially when it is expected by the family or the community that the children will continue to practice said religion.
It is hard to say whether I would have the faith that I have if my family were not believers. I think, if I was exposed to the truth which I know to be true, and I was raised in a different home, I would come to the same faith in Jesus Christ that I have - perhaps just not as soon as I did.