I got a simple idea just create a set of User Parameters
Name: dob
User_1$For example: {__Random(1,28)}/${__Random(1,12)}/${__Random(1922,2000)}
It
Name: dob
User_1$: {__Random(1,28)}/${__Random(1,12)}/${__Random(1922,2000)}
It will return like 21a semi-random date in the format DD/09MM/1996YYYY for user 1.