
This signed acknowledgement of paternity can be challenged within 60 days. After 60 days, a signed acknowledgement of paternity can be challenged only on the basis of fraud, duress or material mistake of fact. If a man signs an acknowledgement of paternity then that man can become liable for child support even if he is not the biological father.
If you say you are the father in writing, it may be very difficult to avoid paying child support later on even if DNA evidence proves otherwise. This is because a signed acknowledgement of paternity is extremely difficult to set aside after 60 days.