My sister is 19 and was adopted when she was 18.her and I would like to know if she can revearse the adoption and go back to having her biological parents as her parents?

Why was she adopted at 18, normally at 18 you are a adult and she would have had to request it.

Can you supply more details

This is an interesting question and I've never seen this come up in practice but I did have someone ask about it once.

My hunch is that you could set aside the adoption if there were fraud associated with its issuance or some procedural irregularity in having it granted. Sure. It would be like any other court order or judgment in that respect. Of course there might also be the need to set aside the termination of parental rights of the bio-parents.

If, however, the adoption had been done properly and could not be set aside, then all that could be done would be to do another adoption (back to your bio-parents). That would be it I would think.

I have to say that I'm also curious why she was adopted at the age of 18 and now, a year later, she's changed her mind.

Why does she feel the need to reverse a decision she made when she was already legally an adult? Why be adopted at the age of 18?

A number of people are sort of baffled by the idea of adults being adopted by other adults because they automatically think of child custody and parental obligations of minors which arise from adoptions. But don't forget there is this vast area of law called probate and estate planning that sets forth rights of inheritance of the legal children (even adult children) of others that's got nothing to do with age.

Hey, I'll always be my mom's child even though I'm an adult and that can mean a lot in probate law.

So yes, adults can and often do adopt other adults. It's not as weird as you may think.

The people that adopted her had been wanting to since she was 15 years old. She tought about it for a couple years and when she turned 18 they still wanted to adopt her to be part of their family legally. So she decided she wanted to but now things just went haywire and she wants to go back to the way things were with her bio parents.

Again, this will depend on WHY things went haywire. But it would have to be something significant because she agreed to the adoption.