((a)) The provisions of paragraphs (c), (d), (e), and (g) of , and of paragraph (2) of , shall apply as of the date of birth to a person born out of wedlock if—

((1)) a blood relationship between the person and the father is established by clear and convincing evidence,

((2)) the father had the nationality of the United States at the time of the person’s birth,

((3)) the father (unless deceased) has agreed in writing to provide financial support for the person until the person reaches the age of 18 years, and

((4)) while the person is under the age of 18 years—

((A)) the person is legitimated under the law of the person’s residence or domicile,

((B)) the father acknowledges paternity of the person in writing under oath, or

((C)) the paternity of the person is established by adjudication of a competent court.

((b)) Except as otherwise provided in section 405 of this Act, the provisions of shall apply to a child born out of wedlock on or after , and before , as of the date of birth, if the paternity of such child is established at any time while such child is under the age of twenty-one years by legitimation.

((c)) Notwithstanding the provision of subsection (a) of this section, a person born, after , outside the United States and out of wedlock shall be held to have acquired at birth the nationality status of his mother, if the mother had the nationality of the United States at the time of such person’s birth, and if the mother had previously been physically present in the United States or one of its outlying possessions for a continuous period of one year.