Yes
The best place to start is the county where your adoptive parents were residing during your adoption. Contact the juvenile court or the family court in that county. Also, contact the county located on your birth certificate.
You apply to the court that finalized the adoption. There are 45 circuits in Missouri. Generally, the circuit is where the birth occurred or where the adoptive parents were residing at the time of adoption.
Only upon written consent of the adult sibling can a court order such disclosure.
No, copies of amended birth certificates are held at the Missouri Department of Vital Records.