My brother got a girl pregnant and neather of them want the baby and they both have kids with oter people would I be able 2 adopt the unborn child

Kids cannot be adopted without the parents' consent.

If your brother allows you to adopt the baby then yes but other than that you cannot adopt the child with out their approval.

Sherrie, the mother would have to agree also... but I'm sure you knew that.

Hey now I see. You said "if they don't want it"... I was reading "they don't want you to adopt it". Well that makes it easy. As long as the courts approve, and the parents agree, then you should have no problem adopting the child.