“I don’t buy the articles reasoning that they change the name on the original Birth certificate when a kid is adopted.”
It’s always been my understanding that, in the case of legal adoption, they do issue another birth certificate with the adoptive parent’s name as parent. Back to the days when adoption records were sealed (I think a person couldn’t get them opened until they were either 18 or 21). So, in order for the adopted child to have a birth certificate that might be required for various things - school, passports, etc., they would have the “replacement” document. Also, back in the day, many parents didn’t tell their children they were adopted. There was somewhat of a stigma about it, nothing like today.
The original birth certificate is still available if he was adopted. He would have to petition a court to release it, that is how it works in Massachusetts at least, for a close family member of mine.