I haven't told my parents. I think it's best that way. My mom has MS and it would serve no purpose for her to know except to pass a giant burden onto her. My brother was dx'd last year and has made the same choice. It would crush her to know that we both have it considering the severity of her course of MS.

I never told my dad because I didn't want my mom to know via him.

The rest of my family and my friends know. I have a great support system and my mom never questions why I know so much about MS now...