Parents sometime forget that some of their grown-up jokes are not suitable for their children ears. Usually children see these jokes directly reported to their own person and many of them might seem not the right thing when more carefully analyzed.
Maybe to the parents making fun or saying funny things is something natural but young children and even more the teenagers might find the jokes offensive and uncomfortable.
Parents should really be more careful when playing with words. Here is the funny graphic, where a child interprets his dad’s jokes.