Very simply, in Switzerland, Art. 268 c of the Swiss Civil Code states that an adoptee at the age of 18 is entitled at all times to personal data of the blood parents, and perhaps before the age of 18 in special circumstances. I believe the laws in most European countries are similar. Why is it that we in the U.S., who are adults, often have to spend years and our life savings for information that the rest of the world is entitled to in the first place?
Adoption is less of a “phenomenon” here, it seems to be handled more pragmatically and not influenced by religious fundamentalists- The system is not perfect but light years ahead in terms of protecting the rights of children. There is open discussion about sex, sex education, how to avoid unplanned pregnancies taught from early on in public schools. Birth control is readily available. (wow, how basic, go figure) Yes, it is everything that would make a right wing wack-o cringe.