.Is there a time limit on when I can file for paternity (equitable estoppel)
When a parent wants to try to prove a man’s legal paternity in court, one issue that may be considered is whether or not there is another man who is already acting as the father and whether or not the child (or the man) believes that he is the biological father. Sometimes, a person can be prevented from trying to declare a different man to be the legal father under a legal theory called equitable estoppel. Equitable estoppel basically that means that a person can be prevented from trying to establish paternity out of fairness to a child or man who already believes a different man to be his/her father. However, I do not know whether or not this would apply to your situation or whether or not judges in your state commonly follow this legal principle.
If there is not another man already assuming the “father” role in a child’s life, then I do not know if the person trying to establish paternity may face any obstacles or not or whether there may be any legal arguments that either parent can make to prevent the establishment of paternity.
Hopefully, an attorney can explain this all in more detail and let you know how it all relates to your situation. Here is a link for legal services:LINK.