In Japan, after receiving human papillomavirus vaccination, a significant number of adolescent girls experienced various symptoms, the vast majority of which have been ascribed to chronic regional pain syndrome, orthostatic intolerance, and/or cognitive ...
www.ncbi.nlm.nih.gov
I would've told them to go fuuck themselves; in fact, I have told them exactly that. What are the odds your SON will develop Cervical Cancer, the disease against which this particular vaccine is meant to protect? Precisely ZER0! What are the odds he'll develop health complications from the vaccine, though? GREATER THAN zero! This is a no-brainer. No-one should be FORCED to receive this vaccine, not even girls, and especially not boys, for whom it's physiologically impossible for the latter to get Cervical Cancer...lacking a CERVIX.
The public schools are essentially telling parents, "hey, this is a public school, in the 21st Century, and there's no way we can protect your 11 year old daughter from getting gang raped in our unisex bathrooms; so, we may not be able to keep her from getting pregnant, or herpes, or AIDS, or syphilis, or gonorrhea...or even murdered, BUUUUT, we have this vaccine, which only has a handful of horrible side effects, that only a couple hundred thousand children have reported, worldwide, and we're sufficiently confident that they're caused by this vaccine, that they're legally required to be listed on the insert we haven't provided you, and since we don't want to be sued when your daughter inevitably contracts one of many sexual diseases, from being raped in our unisex bathrooms, we want to, at least, make sure she doesn't get this fatal one...and since we, likewise, don't want to get sued for sexual discrimination, we're going to demand your son get the same vaccination, even though he doesn't even have a cervix...but, the good news is that the pharmaceutical company is cutting the school in on the action, and we really need the money, for all the new unisex bathrooms...so there's that."
A responsible parental response should be, "thanks for the heads up, and have fun with that, but my children are no longer your students; so, fuuck off, now."