There are a number of concrete steps that schools can take to demonstrate their commitment to LGBT inclusiveness. These include implementing LGB-inclusive policies such as employment non-discrimination and anti-harassment as well as providing LGBT-related in-service trainings to all school staff, a Gay Straight Alliance for students and resources on LGBT issues.
The U.S. Supreme Court also has repeatedly made clear its commitment to protect the constitutional right to free speech in school.
The key to helping your child find a healthy way to deal with prejudice is to start early, think about the messages and values you'd like to communicate, and provide your child with the tools that will help him or her face whatever situation may arise.