Every student has its own driving points, and most of the time one of those is to make their parents proud. They (the students) strives hard to give their (the parents) the best achievements they can do.
Moral support is a powerful driving point to a student, especially if it came from its the people he / she cared for.
Also, academically, parents can help their child in terms of his / her assignments as they (the parents) have far more educational experience and knowledge than their own kids.
I therefore conclude, that parents do have a huge effect on every students performance, both academically and emotionally.