Regarding girls playing high school football: We all need to be concerned about high-contact sports (football, soccer, boxing, martial arts) and the safety of all of our young people.
There is strong evidence that contact sports in which the head is "knocked' around a lot can cause permanent brain damage, especially in children under 18. Helmets have been shown not to protect the head in these cases.
Parents and educators would do well to do some research and look to the health and safety of our young people. Dr. Bennet Omalu wrote an enlightening book called "Truth Doesn't Have a Side," which is well worth reading on the subject.
Mary Wright, Tehachapi