Well...You know that your biomother and father dated, but you didn't tell me how you found that out, what I'm thinking is that you asked for non-identifing information from the adoption agency. If that is the case, then they saw it through the courts. It is possible that your biofather was unlocatable at the time, an adoption can take place without the father's signature if they took steps to locate him and were unable to find him.
If your biomother claimed that she didn't know who the father was, then I would say that the biofather would have to be the one to pursue things with opening the files. I'm not positive on this, I'm not an attorney.
Courts normally do not open sealed files, as I mentioned before. What I would suggest you do, if you are attempting to locate your biological parents, would be to go through search measures. Register with the International Soundex Reunion Agency in Carson City, NV. They are a group that has you fill out a form with all of the information that you have (date, time, place of birth etc.) and if your bioparents fill out the form as well, a match can be made. There's lots of info out there, as well as pro's that do adoption searches for a living. You may want to start out at
http://www.adoption.com There is also a group out there called the Adoption Network, that is who I went through when I was in search of my bioparents. They were a wealth of information and search tips that helped me to eventually locate my birth parents.
If you have any questions on searching, feel free to write back.
Good luck,
Robin
