Legitimation happens automatically once the biological parents of a child born outside marriage marry each other, provided nothing else barred them from marrying at the time of conception. To reflect this on official records, the parents (or a proper representative) still need to execute and file an affidavit of legitimation with the local civil registrar where the child’s birth was recorded.
Legitimation happens automatically by operation of law the moment the biological parents of a child born outside marriage marry each other — but the child does not get a new, legitimate-status birth certificate until the parents (or a proper representative) file an affidavit of legitimation with the local civil registrar where the child’s birth was recorded, so that the record can be annotated. There is no strict deadline in the law itself, but delaying it leaves the child’s PSA documents inconsistent with their actual status, which causes problems later for school, passport, and inheritance purposes.
What Legitimation Means and Who Qualifies
Under the Family Code, as amended by Republic Act No. 9858, children conceived and born outside of wedlock may be legitimated if, at the time the child was conceived, the parents were not legally barred from marrying each other — or were barred only because one or both of them was below eighteen years old at the time. This second branch, added by RA 9858, was meant to cover the common situation of teenage parents who could not marry when the child was conceived because they were minors, but who married once both reached legal age.
What this means in practice: legitimation is not available if the parents could not have married each other for some other legal reason at the time of conception — for example, if either of them was already married to someone else, or they were relatives within a prohibited degree. It is available if the only obstacle was age, or if there was no obstacle at all and the parents simply had not yet married.
How Legitimation Happens: The Subsequent Marriage
Legitimation takes place by the subsequent valid marriage between the parents. The law is specific that it must be a valid marriage; however, if the marriage later turns out to be voidable and is annulled, the legitimation already granted to the child is not affected — it stands. This is different from a marriage that was void from the start, which generally cannot serve as the basis for legitimation at all, since a void marriage does not produce the legal effects a valid marriage does.
What Legitimation Changes for the Child
Once legitimated, the child enjoys the same rights as a legitimate child — the same rights to support, to the parents’ surname, and to inherit as a legitimate child, rather than the lesser share the law gives to illegitimate children. Because legitimation retroacts to the time of the child’s birth, the child is treated, for legal purposes, as if they had been legitimate from birth, not merely from the date the parents married.
Because a legitimated child becomes, for all legal purposes, a legitimate child, they take the father’s surname automatically once the annotation is completed — there is no need for the separate process illegitimate children must go through under Republic Act No. 9255 to use the father’s surname, since that process exists precisely for children who remain illegitimate.
Step-by-Step: Registering the Affidavit of Legitimation
The mechanics of legitimation are handled at the civil registry level, not in court, which is what makes this route considerably simpler and less costly than a judicial proceeding. In broad strokes:
- Gather the documents. This typically includes the child’s PSA-issued birth certificate, the parents’ PSA-issued marriage certificate, and valid government-issued identification of both parents.
- Execute the affidavit of legitimation. Both parents jointly execute and sign the affidavit before a person authorized to administer oaths. If one parent has died or is otherwise unable to sign, the surviving or capable parent may need to explain this and provide supporting proof (such as a death certificate), since the civil registrar will want to be satisfied the marriage and legitimation requirements are genuinely met.
- File it with the Local Civil Registry Office (LCRO) where the child’s birth was originally registered. If the child was born abroad, the affidavit is filed with the Philippine Foreign Service Post that has jurisdiction over the place of birth, or, for a Filipino residing abroad whose child was born in the Philippines, still with the LCRO of the place of birth.
- LCRO reviews and annotates. Once satisfied that the requirements are met, the civil registrar annotates the child’s existing record of birth to reflect the legitimation and, where applicable, the change of surname.
- Request an updated PSA copy. After the LCRO transmits the annotated record, the PSA updates its database, and the family can request a fresh PSA-certified copy of the birth certificate reflecting the annotation.
Special Case: Parents Who Were Minors at Conception
RA 9858 was passed precisely because, before it, a child conceived while either parent was under eighteen could not be legitimated even after the parents grew up and married — the law read the “impediment to marry” requirement strictly, and minority was treated the same as any other legal impediment. RA 9858 carved out an exception: if the only reason the parents could not marry at the time of conception was that one or both were minors, the child can still be legitimated once the parents do marry, whether that marriage happens while they are still young or years later.
If the Child Has Already Died
Legitimation is not lost simply because the child did not live to see the parents’ marriage. If a child who would have qualified for legitimation died before the marriage took place, the legitimation still benefits that child’s own descendants — meaning grandchildren of the parents through that child can claim the legal benefits legitimation would have conferred, most importantly for purposes of succession.
Can Legitimation Be Challenged?
Legitimation is not automatically final and unchallengeable. The law allows it to be impugned, but only by persons who are actually prejudiced in their rights by it — typically other heirs whose inheritance shares would shrink because of the legitimated child’s new status — and only within five years from the time their cause of action accrues. Someone with no real stake in the outcome cannot contest a legitimation just because they disagree with it.
Costs and Timeline
Registering an affidavit of legitimation is far less expensive than any court proceeding, since it does not involve filing fees for a civil case, publication, or a lawyer appearing in court. The realistic costs are: the local civil registry’s registration and annotation fees, which are set by local ordinance and therefore vary from one city or municipality to another; the cost of notarizing the affidavit if it is not signed directly before the civil registrar; and the fees for requesting fresh PSA copies of the annotated birth certificate once the annotation has gone through. Because these are set locally and by PSA channel (walk-in, online, or through a satellite office), it is worth asking the specific LCRO for its current fee schedule rather than assuming a fixed nationwide amount.
Timing depends heavily on the LCRO’s workload and how quickly the annotated record is transmitted to and processed by the PSA. Filing the affidavit itself is usually done in a single visit once the documents are complete, but seeing the annotation reflected on a newly issued PSA copy can take anywhere from a few weeks to a few months.
Common Mistakes That Delay Legitimation
A few recurring issues slow this process down in practice. Parents sometimes assume legitimation is automatic and never file the affidavit at all, leaving the child’s official documents permanently out of step with their true status. Others file using a marriage certificate that has not yet been registered or released by the PSA, which the civil registrar cannot act on. And in blended-family situations, parents sometimes overlook that one of them had a prior undissolved marriage at the time of conception — which is a real impediment, not just age — making the child ineligible for legitimation under the law regardless of a later marriage.
Frequently Asked Questions
Does legitimation happen automatically when parents marry, or do we still need to file something? The legal status changes automatically at the moment of marriage, but the child’s birth certificate will not reflect it until the parents file and register an affidavit of legitimation with the local civil registrar, so filing is still necessary for the record to match the child’s actual status.
Can legitimation still happen if one parent died before the marriage could take place? Legitimation requires an actual marriage between the parents, so if a parent died before the wedding could happen, legitimation through marriage is no longer possible for that relationship; other remedies, such as acknowledgment and support claims, are separate matters.
Will the child's surname change automatically once legitimated? Yes, because a legitimated child is treated as a legitimate child for all legal purposes, they take the father’s surname once the local civil registrar annotates the birth record, without needing the separate surname-use process required of illegitimate children.
Is there a deadline for registering the affidavit of legitimation? The law does not set a strict filing deadline, but delaying it leaves the child’s official documents inconsistent with their true legal status, which can complicate school enrollment, passport applications, and inheritance matters later on.
This commentary is for general informational purposes only and does not constitute legal advice. For guidance specific to your situation, please consult a licensed attorney.
Because this is a civil registry process rather than a court case, most delays come down to paperwork, not law — having the right PSA documents ready from the start makes the biggest difference.