Did you know you can get your tubes tied at 18 as long as your parents are ok with it?

I was seriously considering getting my tubes tied since i'm 18 and figured might as well get it done before i'm 21 since i don't ever intend on having kids. I went to my doctor today and they said that my parents would have to sign off on it for it to happen and it feels so ridiculous, i'm an adult, what do they have to do with it?