Short answer. Three days. Article 255 defines infanticide as the killing of a child less than three days of age, so once the child has reached three days the offence is no longer infanticide and is classified instead by the relationship between the parties or by the circumstances of the killing.
What the law says
shall be imposed upon any person who shall kill any child less than three days of age
Revised Penal Code, Article 255 — Infanticide Of A Newborn. Read the full provision →
What the law says
Any person who shall kill his father, mother, or child, whether legitimate or illegitimate, or any of his ascendants or descendants, or his spouse, shall be guilty of parricide
Revised Penal Code, Article 246 — Parricide: Killing A Relative. Read the full provision →
The line is drawn by days, not by any other test
Article 255 fixes the class of infanticide by a single measurement: the penalty shall be imposed upon any person who shall kill any child less than three days of age. Not by weight, viability, or whether the child had been registered — only by age counted in days. Because the phrase is less than three days, a child who has completed three days falls outside it. The provision is unusual in the Code for being this mechanical, and that is precisely its function: it removes argument about where one classification ends and another begins.
What the offence becomes on the other side of the line
Once the child is three days old, the killing is classified in the ordinary way. Where the offender is a parent, Article 246 applies, since it reaches anyone who shall kill his father, mother, or child, whether legitimate or illegitimate, or any of his ascendants or descendants, or his spouse. Where the offender stands in no such relationship, the killing is prosecuted as homicide or as murder according to the circumstances alleged. So the age of the child decides which enquiry is made, and the relationship decides the answer within it.
Who committed the act still matters inside the three days
Article 255 is not a single uniform rule. It applies to any person, but it then treats the mother separately where the act was done for the purpose of concealing her dishonour, and provides a different penalty again where the maternal grandparents acted for that same purpose. Those distinctions turn on identity and purpose rather than on the age of the child, which remains the threshold question. In other words, the three-day rule settles what the offence is called; it does not by itself settle what follows from it.
The document that decides it
Age in days is proved, not estimated, and the record of birth is what proves it. Where a birth was not registered promptly, or where the recorded time of birth is imprecise, the classification can genuinely be in issue and the medical records surrounding the birth become important. Anyone involved in a case of this kind — on either side — should secure those records early, because they are the point on which the entire classification rests and they are not easily reconstructed later.
Related provisions
- Revised Penal Code, Article 255 — Infanticide Of A Newborn
- Revised Penal Code, Article 246 — Parricide: Killing A Relative