I was also adopted as an infant, and know a little about my biological heritage (I know that I'm dutch, english, french, german, irish, and scottish). My cultural (adopted) heritage is polish, german, and italian. So I relate to all 8 heritages. I've always been the most interested in german (because it is a unifying heritage) and irish (because of my name, and my parents seem to think that the irish heritage is dominant - whether they know this or only suspect this, I'm not sure).
I've been mildly curious about the bio family, but not enough to do any digging (it's pretty straightforward through the agency I was adopted through - Catholic Social Services, but there are fees, and I'm not interested enough to pay I guess).
With some of my current health issues, I've thought of it more recently, but I'm not sure I actually want actual contact with any of the biofamily - and the kinkd of medical info I would want probably wasn't recorded 41 years ago, so I'd pretty much have to contact actual people to find out the info. Not sure I want to do that, because I have mixed feelings about contacting bioparents. It isn't that I wouldn't like to meet them, but they're strangers to me, and probably wouldn't ever be much more than that. I would think that might be hard for a bio mom to take, as she might have been thinking of me as a daughter for all these years, but for me she would mostly be only a means of satisfying my curiosity.
My bond is definitely to my adoptive family, and I'm not sure what meeting biofamily would do or what impact it would have on everyone's feelings. Part of my decision is based on knowing it would hurt my mom. She said I should look (at least for medical information), but I know she would be hurt. She definitely had mixed feelings about my brother's contact with his biomom. His biomom found him, and at first they had a lot of emails back and forth and he got a lot of questions answered, but as time went on, she wanted more and more to become a part of his life and basically be "Mom" to him and Grandma" to his kids.
I guess I think if you want to search you have to be prepared for whatever emotional consequences there are. Biofamily might want no contact, or may want more contact than you're wanting. I guess I'm not willing to deal with the hassle of either.