Can parents stop a minor child from giving her baby up for adoption? The minor had the school call the adoption agency? Should a school interfere with that?

A parents can NOT stop a minor from choosing adoption. The choice belongs to the mother/father of the child.

If the minor asked the school for help calling an adoption agency, then yes--the school was fulfilling its obligations of helping the student explore her options.

Nope, unfortunately the grandparents can not stop the mother/father from giving the baby up. BUT IF YOUR WILLING to adopt the baby, there are "grandparents rights" that can come into play. Look into it. I hope that this helps.