Presumed Father: The individual that the law presumes, until shown otherwise, to be the legal father of a child. This may not be the actual biological father of the child. The law in most states creates a "rebuttable presumption" that if a woman conceives or gives birth to a child while she is married, her husband will be "presumed" to be the father of the child. A similar "presumption" can also be created if a father voluntarily allows his name to be placed on a child's birth certificate. These legal presumptions will remain effective until they are successfully "rebutted," or challenged by someone in a formal legal proceeding.