The Smith Law Offices, P.C. - In Arizona, you can establish a father's paternity by having both parents sign an acknowledgement of paternity form in the presence of a witness or notary. You will generally need a photo ID. You may even have been given this form when your baby was born. You don't even need to have a paternity test done.
In Arizona, the law assumes that the child of a married woman belongs to her spouse, but this is not always the case. When it is not, the parents need to establish legal paternity. This could be necessary, for example, when: