1) Why “legitimate vs. illegitimate” matters in succession

In Philippine private law, a child’s status (legitimate, illegitimate, legitimated, adopted) directly affects:

Whether the child is a compulsory heir
The size of the child’s legitime (the portion of the estate reserved by law)
How the estate is divided in intestate succession (when there is no valid will)
How testamentary dispositions are reduced if they impair legitimes

Even when a will exists, compulsory heirs cannot be disinherited or deprived of their legitimes except for causes and through forms allowed by law.

2) Core concepts you must know

A. Estate, free portion, and legitime

Net estate: what remains after deducting debts, charges, and expenses that the law allows to be deducted.
Legitime: the reserved portion of the net estate that the law mandatorily assigns to certain heirs (compulsory heirs).
Free portion: what remains after legitimes are set aside; this is the part the decedent may freely give by will (or by certain donations, subject to limits and collation rules).

Key rule: You determine the legitimes first; only then can you test whether a will or donation unlawfully cuts into them.

B. Compulsory heirs (those entitled to legitime)

Among the most common compulsory heirs are:

Legitimate children and legitimate descendants
Illegitimate children
Surviving spouse
In certain situations (e.g., no descendants), legitimate parents/ascendants

A child—legitimate or illegitimate—is generally a compulsory heir, but their legitimes differ.

C. “Legitimate,” “illegitimate,” “legitimated,” “adopted”

Legitimate child: generally, a child conceived or born during a valid marriage (and other situations treated by law as legitimate).
Illegitimate child: generally, a child conceived and born outside a valid marriage.
Legitimated child: an originally illegitimate child who becomes legitimate by subsequent marriage of the parents (and compliance with requirements).
Adopted child: for succession purposes, adoption generally places the adoptee in the position of a legitimate child vis-à-vis the adopter, with reciprocal rights, subject to governing adoption laws and the specifics of the adoption.

Because legitimacy affects shares, the first practical legal step in many inheritance disputes is proving the child’s status and filiation.

3) Intestate succession: when there is no will

Intestate succession follows statutory order. In simplified form, when the decedent leaves children:

Children (and their descendants by representation) inherit first.
The surviving spouse concurs with the children.
Parents/ascendants typically inherit only if there are no descendants.

A. If the decedent leaves legitimate children only (plus spouse)

Legitimate children inherit in equal shares.
The surviving spouse concurs with them and receives a share determined by law, typically comparable to a legitimate child’s share in common configurations.

B. If the decedent leaves illegitimate children only (no legitimate children)

Illegitimate children inherit as heirs.
The spouse, if any, also concurs, with shares governed by the Civil Code rules for intestacy.

C. If the decedent leaves both legitimate and illegitimate children

This is the most tested scenario.

Guiding principle in Philippine succession law: In many configurations, an illegitimate child’s share is generally one-half (1/2) of the share of a legitimate child, subject to the presence of other compulsory heirs and the structure of legitimes.

This “half-share” idea is most visible in legitime computations and often carries into how courts and practitioners conceptualize the proportional shares among children when both classes exist.

D. Representation (important for grandchildren)

Legitimate descendants can inherit by right of representation if their parent (a child of the decedent) predeceased, was disqualified, or is otherwise unable to inherit.
Illegitimate descendants’ right to represent is more limited and depends on the legal relationship recognized by law; succession rules also historically restrict certain relationships in the illegitimate line.

Practical takeaway: Whether a grandchild steps into the shoes of a deceased child depends on the legitimacy line and the exact statutory rule applicable.

4) Testate succession: when there is a will

A will can distribute the estate, but only within the limits of legitimes.

A. The will cannot impair legitimes

If a will gives too much to one heir or a stranger, leaving insufficient legitime for compulsory heirs, the excess is reduced through reduction of testamentary dispositions.

B. Children as compulsory heirs in testate succession

Legitimate children: entitled to a larger legitime.
Illegitimate children: entitled to a legitime that is generally one-half of the legitime of a legitimate child, taken in proper proportion with other compulsory heirs.

C. The “free portion” is where flexibility lives

Once legitimes are satisfied:

The decedent may give the free portion to anyone: a spouse, a particular child, a partner, a charity, etc.
However, lifetime donations may be scrutinized if they effectively defeat legitimes.

5) Legitime shares: practical guide to computing children’s protected portions

Philippine legitime computation is technical because shares change depending on which compulsory heirs survive (children, spouse, parents, etc.). Still, for this topic, the most important working rules are:

A. Legitimate children’s legitime

Legitimate children, as a class, are reserved a significant portion of the estate. When they exist, they typically exclude legitimate parents/ascendants from inheriting (ascendants become compulsory heirs only when there are no descendants).

B. Illegitimate children’s legitime relative to legitimate children

As a standard doctrinal anchor in Philippine succession:

Each illegitimate child is entitled to a legitime that is generally one-half of a legitimate child’s legitime/share, when they inherit in concurrence with legitimate children.

This is one of the most commonly applied comparative ratios in succession planning and litigation in mixed-child-status estates.

C. Concurrence with the surviving spouse

The spouse is also a compulsory heir and takes a legitime (or intestate share) that interacts with children’s legitimes. That interaction can change the math significantly.

Practical method lawyers use:

Identify all compulsory heirs.
Determine the legitime pool(s) and statutory proportions.
Allocate shares among legitimate children.
Allocate illegitimate children’s shares as required (commonly half of a legitimate child’s portion in many scenarios).
Check if any testamentary gifts/donations impair the computed legitimes.
Apply reduction/collation rules.

6) A clear illustrative example (conceptual, not a substitute for case-specific computation)

Scenario: Decedent leaves:

2 legitimate children (L1, L2)
1 illegitimate child (I1)
Surviving spouse (S)
Net estate = ₱12,000,000

In many common structures, practitioners think in “units”:

Give each legitimate child 2 units
Give each illegitimate child 1 unit (half of legitimate child)
Then incorporate the spouse’s statutory share depending on whether intestate or testate, and the applicable legitime rules.

The actual final numbers depend on whether there is a will, whether legitimes are being computed, and which exact statutory provisions apply (including spouse concurrence rules). The key point is how the half-share relationship often drives the baseline proportionality between legitimate and illegitimate children.

7) Proving filiation: the gatekeeper issue in inheritance cases

Inheritance rights don’t exist in a vacuum; the claimant must establish filiation.

A. Legitimate filiation

Typically shown through:

Birth certificate and the fact of the parents’ valid marriage
Presumptions of legitimacy for children conceived/born during marriage
Court judgments where legitimacy is contested

B. Illegitimate filiation

Often proven by:

Recognition (in the record of birth, a public instrument, a private handwritten instrument signed by the parent)
Open and continuous possession of status (publicly treated as the parent’s child)
Judicial action to establish filiation, subject to procedural and evidentiary rules

Without proof of filiation, there is no enforceable successional right.

8) Legitimation: when an illegitimate child becomes legitimate

Legitimation generally requires:

The child was conceived and born of parents who, at the time of conception, were not disqualified by an impediment that cannot be removed (the exact statutory conditions matter).
The parents subsequently contract a valid marriage.

Effect:

The child becomes legitimate and gains the successional rights of a legitimate child, including the larger legitime.

9) Adoption and inheritance

Adoption is designed to create a legal parent-child relationship.

General succession consequences:

The adopted child inherits from the adopter as a child would.
The adopter inherits from the adopted child in reciprocal fashion, subject to the governing adoption framework and how it treats ties with biological parents (these details can vary depending on the law applied and the adoption’s legal effects).

Because adoption law has evolved, determining the exact inheritance consequences in a particular adoption scenario is fact- and law-specific.

10) Disinheritance: can a parent cut off a child?

A compulsory heir (including a legitimate or illegitimate child) may be disinherited only if:

There is a legal cause recognized by law, and
The disinheritance is made in a valid will, and
The formal and substantive requirements are met

If disinheritance is defective (no lawful cause, improper form, or unproven cause), the child’s legitime is restored.

11) Lifetime gifts, collation, and “hidden” inheritance issues

A. Donations that impair legitimes can be reduced

Even if property was given away during lifetime, it may be brought into the accounting if it effectively deprives compulsory heirs of legitimes.

B. Collation (bringing gifts into account)

In many family estates, some children received advances (e.g., land, tuition, business capital). Certain transfers may be treated as advancements and must be considered to equalize partitions, depending on the parties and the nature of the donation.

Why this matters in legitimacy disputes: If legitimate children received large lifetime donations and an illegitimate child later claims a legitime, the estate accounting can become complex, and the estate may seek collation/reduction to satisfy compulsory shares.

12) Partition, settlement, and litigation routes

A. Extrajudicial settlement

Possible when:

The decedent left no will
There are no unpaid debts (or debts are settled)
All heirs are of age (or represented properly)
The heirs agree on division and execute the required public instrument and publication steps

A disputed illegitimate claim often blocks or complicates extrajudicial settlement.

B. Judicial settlement

Used when:

There is a will to probate
Heirs dispute filiation, shares, properties, or legitimacy
There are creditors, unclear assets, or unwilling heirs

Courts may have to determine:

Who the heirs are
Which properties are part of the estate
The correct legitimes and reductions
The validity of disinheritance or donations

13) Special problem areas in practice

A. “Second families” and overlapping claims

A very common Philippine scenario:

A valid first marriage with legitimate children
A later relationship producing illegitimate children (if no valid subsequent marriage)

This often leads to:

Conflicts over property characterization
Contesting filiation
Disputes over whether transfers were donations, sales, or simulated contracts

B. Property regime effects (marital property vs. estate property)

Before dividing inheritance:

Determine what portion belongs to the surviving spouse as owner under the marital property regime.
Only the decedent’s share goes into the estate for succession.

Many inheritance fights are actually property-regime fights first.

C. Titles and “estate property” identification

Land titled in one person’s name may still be:

Conjugal/community property
Partly owned
Subject to prior donations or sales
Under trust-like claims

The estate inventory step is crucial.

14) The essential bottom lines

Both legitimate and illegitimate children are generally heirs, but their protected portions differ.
Legitimate children have a larger legitime, and illegitimate children’s legitime is commonly pegged at one-half of a legitimate child’s in mixed-status succession scenarios.
A will cannot override legitimes; excess gifts are reduced.
Most real disputes turn on (a) proof of filiation, (b) property regime, and (c) estate accounting (donations, collation, reduction).
Status can change rights: legitimation and adoption can elevate or reshape successional standing.