In an interesting article, the lives of Ryan Dobson (son of Dr. James Dobson of Focus on the Family), Sean McDowell (son of author and speaker Josh McDowell), Kyle Strobel (son of author and former Chicago Tribune journalist Lee Strobel), and Amy Warren-Hilliker (daughter of pastor and author Rick Warren) are examined.
I can't say that I know personally any children of "Christian celebrities," much less the "celebrities" themselves. I was a good friend in college with the vocalist for this band, and in high school I was a very good friend with a guy who went on to be in a band with the son of this particular Christian celebrity (the band hasn't been together for years, btw).
However, I can say that in college, I was a friend with the nephew of a well-known California pastor and author (no, not John MacArthur). He is also the grandson of one of my alma mater's former presidents and chancellors. I remember talking with him about that while we were lounging in his grandfather's house one day (his grandfather was not home at the time) and he said, "So many people here are in awe of him, but to me he's just 'Grandpa'."