There absolutely must be early, standardized, age-tailored sex education from at least kindergarden, as well as training in asserting their right to refuse in the face of implied authority by adults.

When you say this, don't ever forget to include the equally necessary part where you have to also teach them that it's ok to assert their right to say yes when it is something that they themselves desire and initiate. It's too often that people try to teach the hypocritical "it's ok to say no" while denying any right to say "yes". Without a "yes", there can not be a "no", it really is that simple.

Just as without a "right", there can be no "wrong".