Quick facts, Birth Mother is 17, Birth Father is 18, the baby is now 5 months. There was an Open Adoption both birth parents gave up their paternal rights. What are their rights, or what can be done to get their baby back? Are the Birth Grandparents able to do anything?

You need an attorney. The adoption papers should have stated the terms of the adoption. If a judge approved them the rights were terminated. Unless the birth parents can prove duress or a lack of understanding or something to overturn the adoption its not likely to be overturned. On the other hand, if the attorney who prepared the adoption didn't know what they were doing there could be loopholes.

"Changing your mind" is not a valid reason in most states to get parental rights back.

Having been through it, I know perfectly well that they ask you, clarify, make sure, and pound into you that this is FOREVER, and they make SURE you understand that. Does that mean most birthparents really understand what they're giving up? Of course not--how could they? But you're talking about a major disruption to the child and to the adoptive family because they "changed their minds".

In most cases, a court isn't going to care--because the court made sure they knew what they were doing when they signed that paperwork.

PS--odds are that the only attorney, rather than Attorney Ad Litem, employed was by the adoptive parents. And they PAID to make sure there were no loopholes.