The simple answer to the question posed above is: Yes, it is possible for you to rescind your acknowledgement or deny paternity even after signing the putative father registry and acknowledging paternity. But, like any other legal issue, especially family law issues, there are exceptions to this general rule and the ability to rescind an acknowledgement rely on the specific circumstances of your case. Now, for the longer answer…
Generally, once you have acknowledged paternity on the putative father registry you may subsequently deny paternity or rescind the acknowledgement at any time before a child support or other order is entered that establishes that you are the father of the child, such as an order of paternity or order of legitimation. If the mother agreed that you were the father of the child and indicated such by signing an acknowledgement of paternity with you, you may rescind your acknowledgement of paternity as long as you do so within 60 days of your initial acknowledgment. Within this time limit, you may rescind your acknowledgment at any time unless a court enters an order finding that you are the father of the child.
Georgia's law regarding the rescission of paternity acknowledgments is codified in O.C.G.A. § 19-7-46.1. According to Georgia law:
A voluntary acknowledgment of paternity or registration with the putative father registry is subject to the right of any signatory to rescind the acknowledgment prior to the date of the support order, any other order adjudicating paternity, or 60 days from the signing of the agreement, whichever is earliest. Recording such information in the putative father registry shall constitute a legal determination of paternity for purposes of establishing a future order for support, visitation privileges, and other matters under § 19-7-51.
After the 60-day rescission period, the signed voluntary acknowledgment of paternity may be challenged in court only on the basis of fraud, duress, or material mistake of fact, with the burden of proof on the person challenging the acknowledgment. The legal responsibilities of any signatory, including child support obligations, arising from the acknowledgment may not be suspended during the challenge, except for good cause shown.
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If, after this 60 day period, you later find that you are not in fact the father of the child all hope is not lost. However, after the time limit is lapsed it will be necessary to contact a Georgia paternity attorney to aid you with the process of rescind your acknowledgment and disestablishing paternity.