PATERNITY AND FILIATION
Chapter 1. Legitimate Children
Art. 163. The filiation of children may be by nature or by adoption. Natural filiation may be legitimate or illegitimate. (n)
Art. 164. Children conceived or born during the marriage of the parents are legitimate.
Children conceived as a result of artificial insemination of the wife with the sperm of the husband or that of a donor or both are likewise legitimate children of the husband and his wife, provided, that both of them authorized or ratified such insemination in a written instrument executed and signed by them before the birth of the child. The instrument shall be recorded in the civil registry together with the birth certificate of the child. (55a, 258a)
Art. 165. Children conceived and born outside a valid marriage are illegitimate, unless otherwise provided in this Code. (n)
Art. 166. Legitimacy of a child may be impugned only on the following grounds:
(1) That it was physically impossible for the husband to have sexual intercourse with his wife within the first 120 days of the 300 days which immediately preceded the birth of the child because of:
(a) the physical incapacity of the husband to have sexual intercourse with his wife;
(b) the fact that the husband and wife were living separately in such a way that sexual intercourse was not possible; or
(c) serious illness of the husband, which absolutely prevented sexual intercourse;
(2) That it is proved that for biological or other scientific reasons, the child could not have been that of the husband, except in the instance provided in the second paragraph of Article 164; or
(3) That in case of children conceived through artificial insemination, the written authorization or ratification of either parent was obtained through mistake, fraud, violence, intimidation, or undue influence. (255a)
Art. 167. The child shall be considered legitimate although the mother may have declared against its legitimacy or may have been sentenced as an adulteress. (256a)
Art. 168. If the marriage is terminated and the mother contracted another marriage within three hundred days after such termination of the former marriage, these rules shall govern in the absence of proof to the contrary:
(1) A child born before one hundred eighty days after the solemnization of the subsequent marriage is considered to have been conceived during the former marriage, provided it be born within three hundred days after the termination of the former marriage;
(2) A child born after one hundred eighty days following the celebration of the subsequent marriage is considered to have been conceived during such marriage, even though it be born within the three hundred days after the termination of the former marriage. (259a)
Art. 169. The legitimacy or illegitimacy of a child born after three hundred days following the termination of the marriage shall be proved by whoever alleges such legitimacy or illegitimacy. (261a)
Art. 170. The action to impugn the legitimacy of the child shall be brought within one year from the knowledge of the birth or its recording in the civil register, if the husband or, in a proper case, any of his heirs, should reside in the city or municipality where the birth took place or was recorded.
If the husband or, in his default, all of his heirs do not reside at the place of birth as defined in the first paragraph or where it was recorded, the period shall be two years if they should reside in the Philippines; and three years if abroad. If the birth of the child has been concealed from or was unknown to the husband or his heirs, the period shall be counted from the discovery or knowledge of the birth of the child or of the fact of registration of said birth, whichever is earlier. (263a)
Art. 171. The heirs of the husband may impugn the filiation of the child within the period prescribed in the preceding article only in the following cases:
(1) If the husband should died before the expiration of the period fixed for bringing his action;
(2) If he should die after the filing of the complaint without having desisted therefrom; or
(3) If the child was born after the death of the husband. (262a)
Chapter 2. Proof of Filiation
Art. 172. The filiation of legitimate children is established by any of the following:
(1) The record of birth appearing in the civil register or a final judgment; or
(2) An admission of legitimate filiation in a public document or a private handwritten instrument and signed by the parent concerned.
In the absence of the foregoing evidence, the legitimate filiation shall be proved by:
(1) The open and continuous possession of the status of a legitimate child; or
(2) Any other means allowed by the Rules of Court and special laws. (265a, 266a, 267a)
Art. 173. The action to claim legitimacy may be brought by the child during his or her lifetime and shall be transmitted to the heirs should the child die during minority or in a state of insanity.
In these cases, the heirs shall have a period of five years within which to institute the action.
Art. 174. Legitimate children shall have the right:
(1) To bear the surnames of the father and the mother, in conformity with the provisions of the Civil Code on Surnames;
(2) To receive support from their parents, their ascendants, and in proper cases, their brothers and sisters, in conformity with the provisions of this Code on Support; and
(3) To be entitled to the legitimate and other successional rights granted to them by the Civil Code. (264a)
Chapter 3. Illegitimate Children
Art. 175. Illegitimate children may establish their illegitimate filiation in the same way and on the same evidence as legitimate children.
The action must be brought within the same period specified in Article 173, except when the action is based on the second paragraph of Article 172, in which case the action may be brought during the lifetime of the alleged parent. (289a)
Art. 176. Illegitimate children shall use the surname and shall be under the parental authority of their mother, and shall be entitled to support in conformity with this Code. The legitime of each illegitimate child shall consist of one-half of the legitime of a legitimate child. Except for this modification, all other provisions in the Civil Code governing successional rights shall remain in force. (287a)
Chapter 4. Legitimated Children
Art. 177. Only children conceived and born outside of wedlock of parents who, at the time of the conception of the former, were not disqualified by any impediment to marry each other may be legitimated. (269a)
Art. 178. Legitimation shall take place by a subsequent valid marriage between parents. The annulment of a voidable marriage shall not affect the legitimation. (270a)
Art. 179. Legitimated children shall enjoy the same rights as legitimate children. (272a)
Art. 180. The effects of legitimation shall retroact to the time of the child's birth. (273a)
Art. 181. The legitimation of children who died before the celebration of the marriage shall benefit their descendants. (274)
Art. 182. Legitimation may be impugned only by those who are prejudiced in their rights, within five years from the time their cause of action accrues. (275a)