When an adoption is finalized, the original birth record is sealed by the court and an amended birth record listing the names of the adoptive parents replaces the original. This is a routine procedure. The amended birth record is virtually identical to the original, with the names of the biological parents replaced with those of the adoptive parents. This, of course, gives the impression that the individual to whom the record refers is the biological child of the adoptive parents. However, there is a conspicuous difference: an original birth record bears the signature of the biological mother who signed at the time of the child's birth, while the typed name of the adoptive mother appears in the field intended for the mother's signature in the amended record. (A birth record bearing a typed named rather than a mother's signature is likely an amended record due to adoption.) While birth records sealed by the court at the time of adoption should not appear in the California Birth Index, some have been overlooked and do appear. I am not aware of any instances of amended birth records appearing in the California Birth Index, however they may. I hope this is helpful.