Short answer. Illegitimate. Children conceived and born outside a valid marriage are illegitimate unless the Code provides otherwise, and length of cohabitation is not one of the exceptions. Thirty years of living as husband and wife does not become a marriage by the passage of time.
What the law says
Children conceived and born outside a valid marriage are illegitimate, unless otherwise provided in this Code.
Family Code, Article 165 — Who Is an Illegitimate Child. Read the full provision →
The test is the marriage, not the household
The article makes status turn on a single fact: whether there was a valid marriage. It does not ask whether the parents were faithful, whether they presented themselves to the community as spouses, whether they raised the children together, or how many years they were under one roof. There is no doctrine in Philippine law by which a long union ripens into a marriage on its own. That is a hard thing to read about one's own parents, and it is better learned now than at the moment an estate is being settled.
Illegitimate does not mean without rights
The label allocates rights; it does not withhold them. An illegitimate child is entitled to support from the parent and inherits from that parent, though the share the law reserves is smaller than a legitimate child's. What the status does affect, besides the size of that share, is parental authority and the surname the child uses, which follow different rules for illegitimate children. So the practical consequences are real and worth understanding specifically, rather than treated as a single stigma.
Filiation still has to be proved
A separate question hides behind the first, and it is usually the one that decides cases: proving that this parent is the child's parent. For a child of unmarried parents there is no marriage to work from, so the proof comes from the record of the parent's own acknowledgement — the birth certificate and who signed it, an admission in a public document or a signed private handwritten instrument, and the continuous evidence of the relationship. Where the father died without ever putting anything in writing, this is where the difficulty lies, not in the wording of Art. 165.
If they did eventually marry, ask about legitimation
The article's own qualifier — unless otherwise provided in this Code — points to the exceptions, and the one that most often applies to a couple like your parents is legitimation, which operates where the parents afterwards marry and its own requirements are met. Its effects retroact to the time of the child's birth, so it is not merely prospective. Gather the parents' marriage certificate if one exists, the children's birth certificates, and any document in which a parent acknowledged a child, and take the question to a lawyer with those in hand.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Republic of the Philippines vs. Linney Jean L. Tangarorang and Ramer R. Tangarorang, G.R. No. 272006, February 5, 2025 — read the decision on LawPhil →
- Amadea Angela K. Aquino vs. Rodolfo C. Aquino and Abdulah C. Aquino/Rodolfo C. Aquino, G.R. No. 208912 / G.R. No. 209018, December 7, 2021 — read the decision on LawPhil →
- Alejandra Arado, et al. vs. Anacleto Alcoran and Elenette Sunjaco, G.R. No. 163362, July 8, 2015 — read the decision on LawPhil →
- Juan De Delos Carlos vs. Felicidad Sandoval, et al, G.R. No. 179922, December 16, 2008 — read the decision on LawPhil →
Related provisions
- Family Code, Article 165 — Who Is an Illegitimate Child
- Family Code, Article 180 — Legitimation Retroacts to Birth