Do I have to hire an attorney

  Sorry for your predicament.  This is a tricky area.  Although the woman has another man's name on the birth certificate, that does not definitively establish that he is the father.  She could have filled in his name herself without his consent.  Even then, the birth certificate alone creates a presumption of paternity, not a definite establishment of the fact.  And, at this point, you do not know what has and has not been actually done in the ensuing years since the child's birth.   As to your obligation if paternity is pursued (and with it child support), typically  you can request that there be a paternity test as  you absolutely should.  At most you would be responsible for 24 months of retroactive support from the time a paternity action is filed if the child is yours.    However, if you are receiving letters from the Department of Revenue rather that being served with papers by a process server from  the circuit court that is another rabbit hole you don't want to go down.  MAKE SURE IF YOU'VE RECEIVED ANYTHING THAT YOU COMPLY WITH ANY DEADLINES IN THE LETTER TO OBJECT AND IF YOU'VE BEEN SERVED WITH COURT PAPERS FROM A PROCESS SERVER THAT YOU DO SOMETHING BEFORE THE 20 DAYS EXPIRES.   Since this is a bit complicated, it would definitely serve you well to consult with an attorney near where you live.  The consequences of not making the right move could obligate you to pay for a child that is not yours (maybe) and even if the child is yours, paying does not give you a right to start a relationship with the child absent filing the proper papers to do so (whcih, for all intents and purposes cannot be done in an administrative proceeding)   I hope this helps send you in the right direction.   Best regards, Cindy Vova Law Offices of Cindy S. Vova, P.A. Broward/Boca Raton 954-316-3496/561-962-2785