My sons biological father promised to pay for his college when he was just a baby. Now that my son is 20, he is refusing to acknowledge him, let alone help financially. Is they're anything I can do to make him stand by him and help as promised? I've been a single mom since he was a baby an cannot afford to help like I want to.

My sons father is not the man listed on the birth certificate. Both men are aware of this and why it was done. The man on the certificate has been paying child support. Is it possible to go back and do a DNA and reassign the certificate and child support payments.

Not unless there is a court order saying so. His obligations have ended as far a involuntary financial support.

Maybe. Since we don't know where you are then we can't really answer with any certainty.

And why did both mean allow this and why did the one comment a crime by signing form stating they knew they were the father.

The one man who is not the father, will need to file an objection. Or the one who is , will need to file for his rights.

In many places it will be allowed, in some, there is a time frame, in others it will not be possilbe.

So a visit to the local lawyers since they will be needed anyway

What was the child support order that the court issued, years ago, say about this.

I've merged these two threads since they both contain info that bears on the other question. Based on the info provided, I think you are out of luck. In most states (ANY question on law needs to include your general locale as laws vary by area. ) any challenge to paternity must be mounted before the child turns 18. Since the child is now 20 it would probably be too late. So the man who signed the birth certificate and acknowledged paternity is the legal father and responsible for support. If this is not the bio father, then the bio father has no legal obligation anymore.