Your granddaughters more than likely are already familiar with the dangers that are out there. Take the time to talk to your grandsons about being men with the courage to stand up to their friends and condemn their friends when they’re cat-calling girls, trying to get girls drunk to sleep with them, and being misogynistic. Educate them on the inhumane ways other men prey on women, and teach them to stand up for women. Women are told all the time to watch their drinks, to be careful when they go out… let’s start teaching our sons to stop raping people.
(I am of course naively assuming you have grandsons. If you don’t, I’m sure you can still find some boy in your neighborhood and educate him.)