Well, calling him out of the blue could be quite distressing to him. If she is in contact with him, maybe she can ask how he feels. If not, maybe she has an email or mailing address for him. Sending him a brief letter might be better, and give him time to process his feelings before responding. A phone call out of the blue won't give him that chance.
If you contact him, you should consider keeping your message positive - about what's gone right in your life, how good your adoptive parents are, etc., and then simply tell him that you're curious about him and would love to have the chance to connect with him. Saying "connect" instead of "meet" leaves the communications options open for him. You can see where it goes from there.
yesterday, I was talking to my biological mother on facebook, and she confirmed that the man I believed to be my father is indeed my father. She gave me his phone number, and now...I have no clue what I would say to him.
know that perhaps for a long time that you probably cannot find your parents. I am adopted as well but i have met my birthfamily, but not my mother or father. try and ask a few trick questions. if he is your father i congradulate you whole-heartedly. but it wont hurt to try.