Once you adopt a child, they are your child in every legal way. You receive a new birth certificate that has you listed as the parent. You have the right to make every day decisions in the same way as you would your birth children. You also have a say into whether or not you continue contact with the birth family.
I do strongly recommend trying to keep in contact with any of the birth family that are safe connections for your child. For some children, this is not possible due to safety risks.
If possible, in the long run, keeping these connections positively impacts your child through feeling connected with where they come from. It positively impacts the adoptive parents to be able to tell your child that this piece of who they are, their history, mattered enough for you to go through the effort of maintaining contact. And, an extra bonus, there is something wonderful about not having to wonder if your child(ren) will want to seek out their birth family when they come of age because you have already provided them with that missing piece.
Thank you for your great question! If you have questions, send them to #youaskedfa or Kim@fosteraz.com