ISO bi racial male born in St. Louis Mo and adopted to KS couple in 1990 DOB 1-28-90

Birth mother ISO son born in January 1990. Mother, Julie Noll and father, Eric White. Birth mother & birth father are still friends and we are searching jointly for birth son. Not sure if we need to register in MO or KS. Child was born in MO but adoptive parents are in KS. Any advice is appreciated.