Do your parents both need to agree to have your belly on periced?

okk so i just had a doctors check up and the doctor said i have the right kind of belly on and to have it peirced and my mom said yes. my parents are divorced and she said that he will not say yes and she said that he doesnt have to agree that we can just go get it done with out him knowing. so do both of your parents have to be there and/or agree with it being done??