What is the best possible way to find an adoptee's birth family?

[Juanaquena]

You do not indicate if you wish to find information on someone in your family in the past and who is now no longer alive or if you are seeking the birth parents of someone who was adopted and who is now alive.

If you are conducting genealogy research (researching one's family tree/family history) of someone who is deceased, you may find some tips on this Rootsweb.com guide web page:
http://rwguide.rootsweb.ancestry.com/lesson31.htm

Keep in mind that you may not find the info you seek. There just may not be any records that are open and not sealed (not available to anyone.)

If you are seeking info about the birth parents of someone who is still alive, there are web sites for adoptees and their birth parents to post queries in hopes of connecting.

Here are some links:
http://registry.adoption.com/
http://www.adopteeconnect.com/

Best wishes