You need to have a signed affidavit stating the bio-logical parent will allow the child to leave the country and live in the states. Just a passport isn't sufficiant. You'll need this letter when you go for your interview.
Especially if the parent has joint custody, you'll need the letter. If you have sole custody without any visitations rights I don't think you need the letter. But if the fathers name is on the birth certificate, be prepared to be asked questions at your interview such as , "Does the parent know your moving this child to the states?"
I had a verbal agreement with my daughter's bio dad and he had said when the time came, he would sign the paper to allow her to move. We had joint custody but my daughter had lived with me and saw her bio dad every other weekend.
Unfortunatley we went thru a rather nasty divorce and when it came time to sign the letter to let her move, he refused. This was less then 2 weeks before my interview. I contacted my lawyers but they said it would have taken almost a year to get a court date and less then a 50% chance that the judge would allow her to move.The bio-dad had a well known father's rights lawyer and had tons of money to fight. Her Bio-dad said that he didn't really want her but since I wanted her so bad that he would teach me a lesson for divorcing him and not allow her to go. (Thats ok, Karma will get him!)
In BC Canada, once a child reaches the age of 12 they are allowed to choose whom they want to live with. My child was 10 at the time. I did manage to get a court document that states that when she turns 12 she can move here if she chooses.
I had to leave her with her bio-dad and move without her.
Luckily, She has been able to come down here and visit often. She comes every Christmas, spring break, summer and thanksgiving.
She turns 12 next February and has already chosen to move here. (I knew she would!) We'll start gathering everything for my husband to apply for her visa in January. Hopefully She can finish out her school year in Canada and move here in Summer 2008.