Legitimation:

The legal process in which a natural father can use to acknowledge legally his children who were born out of wedlock (outside of marriage).  A legitimated child can be a “child” under immigration law under these conditions:

• the legitimation took place according to the law of the child’s residence or the father’s residence;
• the father proved (established) that he is the child’s natural father;
• the child was under the age of 18; and
• the child was in the legal custody of the father who legitimated the child when the legal process of legitimization took place