Grey hair

I have grey hair.  Grey hair is under my crazy red hair.  Only my sister, who is my hair stylist, knows how grey my hair really is.  She knows, but she would never say.  She would never say because a) it's against the hair stylist code of ethics (I assume there is one) and b) because she also hides some white stuff with hair dye.

The difference in our hair is that she inherited my mother's mutant early-grey hair gene.  Neither one of us have forgiven mom for passing that on.  My grey hair is not my mother's fault though.  It is Boy and Girl's fault.

How do I know they are responsible?
I know Boy is responsible because tonight I actually felt one grow from the top of my head, just to the left of my right eye (the one that was twitching.)  Boy was in the shop working on his tractor.  He came in the kitchen with an unidentified brown/red smear across his face.  The dirt didn't turn my locks grey, his question did.
"Mom, how up to date is my tetanus shot?"