QUOTE(Meriem_setif @ Feb 8 2008, 04:30 PM)

You said you were born in Canada. I would think that since you were legally adopted in Canada by Canadian citizens then you lost all ties to you birthmom. Even the possible citizenship. I may be wrong. Just my thoughts.
Meriem
I'm not so sure. INA 301 talks about conditions under which a child is a US Citizen on the day the child is born. The details of the rules have changed somewhat over the years, but basically, if you're born of a US Citizen parent who meets the residency requirements, you are automatically a citizen at the moment you are born.
The adoption would have happened after the birth; that is, after the child was already a US Citizen according to US law. There are only a few ways a US citizen can lose US citizenship, and I don't believe adoption is one of them. Lots of other ties may be severed by adoption, of course.
I think the most difficult challenge will be gathering the proof that the citizenship requirements were met at birth. The longer time passes, the more difficult it may become to gain the documentation.
If you do meet the requirements, you can apply directly for a US passport. Or you can apply for a certificate of citizenship; the choice is yours.