I know plenty of people who were adopted. Most of them went out and met their biological parents. It normally goes one of two ways. Either it goes poorly or it goes well.
I guess you could say that about most things but in this case it is particularly interesting. Either you realize you are better off without them, or you have a new, great relationship.
As far as I can tell, no one seems to regret meeting their bio-parents. Good or bad, that knowledge is something worth having.