My son is not school age yet, but I do worry about what might be taught at school, if I choose to send him. I don't worry so much about middle and high school, because by then he will be able to discern fact from opinion, I worry most about the early years, where kids tend to believe whatever grown ups tell them.
However, I do plan to raise my son in a very honest way, and discuss things with him. I want him to be exposed to many varying opinions on subjects, once he is old enough to form an opinion based on his own experiences and values. I don't care if my son has different beliefs than I do on most subjects, and I have no plans on being overprotective about what he is exposed to.
I do have a problem with fear-mongering, though. Like that movie (Mean Girls?) where the teacher says "If you have sex, you WILL get pregnant, and DIE."
I want my son to receive honest information so he can make his decisions appropriately. Even with things I fear, I know I have to teach him honestly and accept his actions, and only try to help him along the way. (For instance, he has a strong family history of addiction, but I can not tell him that he will die if he smokes pot. I plan to explain my preferences for him and my reasons for them, but I will not give him misinformation, no matter how tempting it may be.)
Overall, I think the school should have less influence over kids than their parents. Peer pressure is scary. I was a victim to it many times over, so I know how strong it can be, and how it can make you act against your values. I think when parents rely too strongly on the school to be the sole source of their children's educations, the schools get a similar power over the child, and the child will reject family values in favor of those of the school. It is so important to be an active advocate of your values starting early on, instead of waiting for the school to teach something then attempting to contradict it once it has been drilled into your child's head.