How to expedite a Paternity Test?

the child is 18 years old!, who in their right mind unless money hungry would ever bring it up. My dad had the same problem but hes never payed child support and i don't know why the woman didnt bring it up either. I have all respect for women and no respect for dead beat dads but seriously, hes 18. Let the teenager live their life. Parents need to grow up sometimes.