First of all, you should get the facts straight. While this teacher's behavior would seem inappropriate, it may not be. All of the meetings and phone calls may just be the extra effort of a dedicated teacher. For example, the sessions at the teacher's home could be the innocent meetings of a study group. Also, what time is all hours of the night? Is it a reasonable 10:00 p.m. or a too late 3:00 a.m.? Plus, what are the topics of the phone conversations? Is it possible the teacher is helping the students solve difficult equations?

If you firmly believe that there is a question of impropriety, the person with whom you need to speak is the high school principal. The principal will make sure that your complaint is turned over to the employee responsible for handling all sexual harassment complaints at the school.

Federal law under Title IX requires schools to set up and publish grievance procedures for resolving sexual discrimination complaints so the matter should be resolved swiftly. Of course, the best way for schools to deal with sexual harassment is to prevent it from occurring. Many schools have established discussion groups for both male and female students to talk about what sexual harassment is and how to respond to it in the school setting. If the girl's school has such a program, she will be aware of the appropriateness of the teacher's behavior and how to handle sexual harassment grievances.

Finally, if this is a problem of sexual harassment, it must be nipped in the bud. The school has the obligation to stop it and make sure that it does not happen again.