How can I find out if I am a citizen of USA. I was born in Sweden, adopted in England, moved to USA and adopted in Oregon to my 3rd father. I am 49 years old and will never know my real mother and father, but since I was adopted by my 2nd step dad when I was 12 in Oregon can I use a live birth certificate to obtain a passport?

You need more information from your second and third adoptive parents. How id you enter the US? What was there immigration status? Did they petition for you?