Given a case where the medical histories of the birth parents are available, I see absolutely no justification to know who they were personally.
Since when does one person's curiosity have more justification than another person's right to privacy? Beyond health issues that could impact that or the next generation, I consider releasing identities of donors (sperm, kidneys or whatever) to be an invasion and breach of basic rights. And such demands have already proven to result in unrecoverable drops in donations. If you support genetic donations, you better consider continuing to protect the rights of the donors or forget the entire concept.
From the point of view of the offspring, I have to wonder which would be worse:
Knowing only that you were the result of two people giving something of theirs so that your adopting parents could bring you into their world;
or
Knowing that you were something that your birth parents could not deal with the responsibility of having in their lives.
As for surrogates and that whole line, well back to adoptions!
Just because someone can get pregnant does not mean they should.