As an introvert, I think that society is more to blame than parents, generally. I suppose that the main issue is that they might expect the introvert to like the same things that the majority (extroverts) enjoy. Group activities, sports, whatever. Good/astute parents quickly realize that their child is introverted, and will make changes in how they approach the child. That said, there's a general bias against kids who are introverted, generally, in society. I am still struggling with it in my late 30s. Unfortunately, our modern society places stigmas on introverts, and promotes extroverts as the "norm." I think this will change in the future, as people become more aware of the differences in mindsets..