There’s an OIP Opinion Letter that says that once information is made public or published there is no privacy interest in the information any more. The exception to disclosure that is always cited is the privacy exemption - but if the information is already published - say, in a newspaper or on a website - that information isn’t eligible for the privacy exemption.
Also, the legislative history of UIPA shows that the bill’s exemptions were not intended to close information that had previously been authorized for release. So anything that was authorized for disclosure by law before mid-1988 isn’t subject to UIPA’s exemptions. I’ve posted about it at my blog, documenting what I’m saying.
The birth certificate number and date of birth were required to be publicly-accessible as index data before 1988 so those items are not eligible for the privacy exemption that the DOH keeps using.
I don’t know what the requirements are for the hospital but I can almost guarantee you that Obama was not born in a hospital. Some of the reasons why are posted at http://butterdezillion.wordpress.com/2010/01/11/red-flags-in-hawaii-2/
I couldn't say that he was or wasn't, but I can tell you about HIPAA restrictions. A hospital can't say that someone was born in that hospital without a release from the patient. HIPAA does restrict old data - it doesn't matter if it was released before HIPAA, it can't be released now.