Short answer. No, there is no automatic presumption either way. Rule 131, Section 4 says a child born more than three hundred days after a marriage ends or the spouses separate carries no default presumption of legitimacy or illegitimacy, so whoever claims the child is one or the other has to actually prove it with evidence, not rely on an assumption.
What the law says
There is no presumption of legitimacy or illegitimacy of a child born after three hundred [ ] days following the dissolution of the marriage or the separation of the spouses. Whoever alleges the legitimacy or illegitimacy of such child must prove his or her allegation.
Rule 131, Section 4 — No presumption of legitimacy or illegitimacy. Read the full provision →
The three-hundred-day marker
Philippine evidence law generally treats a child conceived or born within a certain window around a marriage as presumptively legitimate, on the reasoning that ordinary gestation periods make that connection likely. Once a birth happens after three hundred [ ] days following the dissolution of the marriage or the separation of the spouses, that ordinary basis for presuming legitimacy no longer holds, because three hundred days is well beyond what an ordinary pregnancy would explain.
Why the rule refuses to presume in either direction
What is notable about Section 4 is that it does not simply flip the earlier presumption around and presume illegitimacy instead. It states plainly that there is no presumption of legitimacy or illegitimacy at all past that point — the law declines to guess either way, because past the ordinary gestation window there is no longer a reliable biological basis for the court to lean on automatically.
Who has to prove what
In place of a presumption, the rule puts the burden squarely on whoever is making the claim: whoever alleges the legitimacy or illegitimacy of such child must prove his or her allegation. That means if you want the child treated as legitimate, you carry the burden of proving it; if someone else wants the child treated as illegitimate, that burden falls on them instead — neither side gets to lean on a default assumption to win by silence.
Why this matters beyond the label itself
Whether a child is treated as legitimate or illegitimate can affect matters like surname, parental authority, and succession rights, so this evidentiary rule is rarely academic. Because no presumption applies once the three-hundred-day mark has passed, the party asserting either status should expect to bring proof — testimony, documents, or other competent evidence — rather than assuming the court will simply accept the claimed status by default, since the burden falls on whichever side is actually making the claim.
Related provisions
- Rule 131, Section 3 — Disputable presumptions
- Rule 131, Section 5 — Presumptions in civil actions and proceedings