text: what's a social security number? what's a social security number? is it given to you when you are born? what is it for? my parents say i don't have one but my little brother does. do i need to get one too? yes. all persons born here are given one. but your parents were supposed to file with the social security office after your birth, or the hospital supplies the forms, the parents fill it out before the mom and baby leave the hospital and then the hospital files it with the social security administration.  if you are not born here, but come legally, you are eligible for one and need to file paperwork with s.s.a.  if you are not here legally, you are not entitled to one.