Legal Question in Family Law in Massachusetts

Most children get their social security numbers well before they are 18 years old. In order for a parent to take a deduction for a child, the child has to have a social security number. So it is most likely he had this information long ago and could legally get from his accountant who prepared his returns prior to your reaching the age of majority or one that has copies of those returns. Once you reach 18 years old and assuming you have more than $600 a year in income you are required to file a federal tax return. You said a few years ago, so if you were 17 at the time, there is nothing wrong with him having the return prepared and signing it as your parent. Once you reached 18 years of age, you should sign any return prepared for you.

He is prohibited from using your social security number for his own gain or purposes (that does not mean he cannot take you as a deduction if he provides more than 50% of your support).