Articles 163 up to 174 of the Family Code deal with the issues of paternity, filiation, and legitimate children. (We will discuss in the next primer the Family Code provisions on illegitimate children.) At the latter portion of this primer are the higlights of the Supreme Court rulings in Locsin vs. Locsin (on the importance of a birth certificate in proving filiation, and the lack of value of an alleged child’s picture taken at the funeral of the alleged father) and De Jesus vs. Dizon (on the presumption that children born in wedlock are legitimate).
What are the kinds of filiation of children?
The filiation of children may be by nature or by adoption. Natural filiation may be legitimate or illegitimate.
What is the status of a child born during the marriage of its parents?
Children conceived or born during the marriage of the parents are legitimate.
What about children conceived by artificial insemination?
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.
Who are illegitimate children?
Children conceived and born outside a valid marriage are illegitimate, unless otherwise provided in the Family Code.
How can the legitimacy of a child be impugned or questioned?
Legitimacy of a child may be impugned only on the following grounds:
 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;
 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
 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.
What if the mother states that her child is in fact illegitimate? What if the mother was sentenced by a court as being an adulteress?
The child is considered legitimate although the mother may have declared against its legitimacy or may have been sentenced as an adulteress.
What rules govern when the marriage is terminated and the mother marries within 3oo days after the former marriage is terminated?
If the marriage is terminated and the mother contracted another marriage within three hundred days after such termination of the former marriage, these rules govern in the absence of proof to the contrary:
 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;
 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.
Who has the burden of proof in proving or disproving the filiation of a child born after 300 days following the termination of the former marriage?
The legitimacy or illegitimacy of a child born after three hundred days following the termination of the marriage must be proved by whoever alleges such legitimacy or illegitimacy.
When should the action to impugn or question the legitimacy of a child be filed in court?
 The action to impugn the legitimacy of the child must 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 paragraph above 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 must 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.
In what instances can the heirs of a husband impugn or question the filiation of an alleged child?
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:
 If the husband should die before the expiration of the period fixed for bringing his action;
 If he should die after the filing of the complaint without having desisted therefrom; or
 If the child was born after the death of the husband.
How can the filiation of legitimate children be proved?
The filiation of legitimate children is established by any of the following:
 The record of birth appearing in the civil register or a final judgment; or
 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 must be proved by:
 The open and continuous possession of the status of a legitimate child; or
 Any other means allowed by the Rules of Court and special laws.
Within what periods should the claim for legitimacy be pursued?
The action to claim legitimacy may be brought by the child during his or her lifetime and will be transmitted to the heirs should the child die during minority or in a state of insanity. In these cases, the heirs have a period of five years within which to institute the action.
What are the rights of legitimate children?
Legitimate children have the right:
 To bear the surnames of the father and the mother, in conformity with the provisions of the Civil Code on Surnames;
 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
 To be entitled to the legitime and other successional rights granted to them by the Civil Code.
Locsin vs. Locsin, G.R. No. 146737, December 10, 2001
A birth certificate is a formidable piece of evidence prescribed by both the Civil Code and Article 172 of the Family Code for purposes of recognition and filiation. However, birth certificate offers only prima facie evidence of filiation and may be refuted by contrary evidence. Its evidentiary worth cannot be sustained where there exists strong, complete and conclusive proof of its falsity or nullity. In this case, respondent's Certificate of Live Birth No. 477 entered in the records of the Local Civil Registry [from which Exhibit "D" was machine copied] has all the badges of nullity. Without doubt, the authentic copy on file in that office was removed and substituted with a falsified Certificate of Live Birth.
Incidentally, respondent's photograph with his mother near the coffin of the late Juan C. Locsin cannot and will not constitute proof of filiation, lest we recklessly set a very dangerous precedent that would encourage and sanction fraudulent claims. Anybody can have a picture taken while standing before a coffin with others and thereafter utilize it in claiming the estate of the deceased.
De Jesus vs. Dizon, G.R. No. 142877, October 2, 2001
The petition involves the case of two illegitimate children who, having been born in lawful wedlock, claim to be the illegitimate scions of the decedent in order to enforce their respective shares in the latter’s estate under the rules on succession.
The filiation of illegitimate children, like legitimate children, is established by (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 thereof, 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. The due recognition of an illegitimate child in a record of birth, a will, a statement before a court of record, or in any authentic writing is, in itself, a consummated act of acknowledgment of the child, and no further court action is required. In fact, any authentic writing is treated not just a ground for compulsory recognition; it is in itself a voluntary recognition that does not require a separate action for judicial approval. Where, instead, a claim for recognition is predicated on other evidence merely tending to prove paternity, i.e., outside of a record of birth, a will, a statement before a court of record or an authentic writing, judicial action within the applicable statute of limitations is essential in order to establish the child’s acknowledgment.
A scrutiny of the records would show that petitioners were born during the marriage of their parents. The certificates of live birth would also identify Danilo de Jesus as being their father.
There is perhaps no presumption of the law more firmly established and founded on sounder morality and more convincing reason than the presumption that children born in wedlock are legitimate. This presumption indeed becomes conclusive in the absence of proof that there is physical impossibility of access between the spouses during the first 120 days of the 300 days which immediately precedes the birth of the child due to (a) the physical incapacity of the husband to have sexual intercourse with his wife; (b) the fact that the husband and wife are living separately in such a way that sexual intercourse is not possible; or (c) serious illness of the husband, which absolutely prevents sexual intercourse.
Succinctly, in an attempt to establish their illegitimate filiation to the late Juan G. Dizon, petitioners, in effect, would impugn their legitimate status as being children of Danilo de Jesus and Carolina Aves de Jesus. This step cannot be aptly done because the law itself establishes the legitimacy of children conceived or born during the marriage of the parents. The presumption of legitimacy fixes a civil status for the child born in wedlock, and only the father, or in exceptional instances the latter’s heirs, can contest in an appropriate action the legitimacy of a child born to his wife. Thus, it is only when the legitimacy of a child has been successfully impugned that the paternity of the husband can be rejected.