I am Canadian and am in the process of preparing the application to sponsor my American Spouse who is residing in the US at the moment. I am confused with the Form 5406. He has grown children living on their own residing in the US. (39-42 years old). Do we need to fill out this form or is this for dependant children only? If we do need to fill out the form, are they required to fill it out themselves and are they required to provide a birth certificate as well? I've searched several different sites and all say something different. They are not immigrating to Canada. They are US citizens. One of the sites said that this form was only for people in other countries, not the US.