I have observed the following on many occasions.

A son or daughter grows up in a Christ-professing home.  Sadly, the parents have not availed themselves of opportunities to grow in their own understanding of the Christian faith.  They can’t interact or answer any of the objections to Christianity that increasingly nag Johnny and Sally.

Johnny and Sally go off to college.  They abandon their Christian upbringing. 

The parents add to their sorrow with the misguided notion that their kiddo abandoned the faith due to “liberal professors.”