Is a person a Christian merely because they have been born into a Christian family? Of course, the thoughtful answer is no, even though a person may subconsciously subsume some surface-level measure of their parents' faith, yet never allow it to make any deeper impact on their life. And then people wonder why have never experienced this "faith" thing!
Rev Victor Shepherd notes in his excellent recent book Do you love me? And other questions Jesus asks:
Christians of every generation are slow to hear that God has no grandchildren. God certainly has children: We become God's children as we seize Jesus Christ in faith and vow never to let go. Grandchildren, however, are those who try to ride the coattails of their parents' faith, sooner or later to find that what they assumed to be possible – faith at arm's length, faith secondhand, faith on the cheap -isn't possible.
If you today are wondering if you have been living as a grandchild, and not a child of God, I implore you to please take a moment to consider what it means to be living a Spirit-filled life! It may be the most important few minutes of the rest of your life!