I. Introduction

Inheritance in the Philippines is governed primarily by the Civil Code of the Philippines, particularly the provisions on succession. Philippine succession law is deeply shaped by family relations. A person’s status as a legitimate child, illegitimate child, surviving spouse, parent, or other relative determines whether that person is a compulsory heir, how much he or she may inherit, and whether the deceased can freely dispose of property by will.

Among the most important distinctions in Philippine inheritance law is the distinction between legitimate children and illegitimate children. Both may inherit, but they do not inherit equally under the Civil Code. Legitimate children generally enjoy stronger inheritance rights, while illegitimate children are granted a legally protected share that is smaller and subject to limitations.

This article discusses the inheritance rights of legitimate and illegitimate children in the Philippine context, including compulsory heirs, legitime, intestate succession, testate succession, representation, disinheritance, proof of filiation, and common practical issues.

II. Basic Concepts in Philippine Succession Law

A. Succession

Succession is the mode by which the property, rights, and obligations of a person are transmitted upon death. The person who died is called the decedent. The persons who inherit are called heirs, devisees, or legatees, depending on the nature and source of the inheritance.

Succession may be:

Testamentary succession – when inheritance is governed by a valid will;
Legal or intestate succession – when there is no will, the will is void, or the will does not dispose of all property;
Mixed succession – partly by will and partly by operation of law.

B. Heirs

An heir succeeds to the whole or a fractional part of the estate. A devisee receives real property by will. A legatee receives personal property by will.

Children, whether legitimate or illegitimate, may be heirs. However, their rights differ depending on their status.

C. Estate

The estate is the total property, rights, and obligations left by the decedent after death. Before distribution, debts, taxes, administration expenses, and other lawful charges are generally settled.

D. Legitime

A central concept in Philippine inheritance law is legitime.

Legitime is that portion of the estate which the law reserves for certain compulsory heirs. The decedent cannot freely give it away by will. Any testamentary disposition that impairs the legitime of compulsory heirs may be reduced.

This means that even if a parent executes a will leaving everything to only one child, to a stranger, or to a charity, the law protects the minimum shares of compulsory heirs.

III. Legitimate and Illegitimate Children: Definitions

A. Legitimate Children

A child is generally considered legitimate if conceived or born during a valid marriage of the parents, subject to rules under the Family Code.

Legitimate children include those whose legitimacy arises from law, such as children born within a valid marriage and, in certain cases, legitimated children.

A legitimated child is one who was originally illegitimate but later becomes legitimate by operation of law, usually when the parents were legally capable of marrying each other at the time of the child’s conception and subsequently validly marry. Once legitimated, the child generally enjoys the same rights as a legitimate child.

B. Illegitimate Children

An illegitimate child is a child conceived and born outside a valid marriage, unless otherwise recognized as legitimate or legitimated under law.

Illegitimate children may inherit from their parents, but their legitime is generally one-half of the legitime of a legitimate child.

IV. Compulsory Heirs

A. Meaning of Compulsory Heirs

Compulsory heirs are heirs whom the law protects by reserving for them a portion of the estate known as the legitime.

The Civil Code recognizes several classes of compulsory heirs, including:

Legitimate children and descendants;
Legitimate parents and ascendants, in proper cases;
Surviving spouse;
Acknowledged natural children and other illegitimate children, under current terminology generally referred to as illegitimate children;
In certain cases, legitimate parents of illegitimate children.

The exact rights of these heirs depend on who survives the decedent.

B. Children as Compulsory Heirs

Both legitimate children and illegitimate children are compulsory heirs of their parents.

However, they do not receive equal legitime. The law gives legitimate children a preferred position.

V. Legitime of Legitimate Children

A. General Rule

When a decedent is survived by legitimate children, the legitimate children are entitled to one-half of the hereditary estate as their collective legitime.

That one-half is divided equally among the legitimate children.

For example, if the net estate is ₱10,000,000 and the decedent is survived by two legitimate children, their collective legitime is ₱5,000,000. Each legitimate child has a legitime of ₱2,500,000.

B. Legitimate Children Exclude Legitimate Parents

If the decedent is survived by legitimate children, the decedent’s legitimate parents or ascendants generally do not receive legitime. Legitimate children exclude legitimate parents in the direct line.

Thus, if a person dies leaving legitimate children and parents, the legitimate children are the preferred compulsory heirs in the direct descending line.

C. Equal Rights Among Legitimate Children

All legitimate children generally inherit equally from their parent, regardless of sex, age, financial condition, or whether one child had a closer relationship with the parent.

Philippine law does not give a larger inheritance share to the eldest child. There is no rule of primogeniture in ordinary Philippine succession law.

VI. Legitime of Illegitimate Children

A. General Rule

Illegitimate children are compulsory heirs. Their legitime is generally one-half of the legitime of each legitimate child.

This does not mean that illegitimate children receive one-half of the estate. It means each illegitimate child receives one-half of the share reserved by law for each legitimate child.

B. Limitation: Must Not Impair Legitimate Children’s Legitime

The legitime of illegitimate children must be taken from the free portion of the estate, and it must not impair the legitime of legitimate children.

This is one of the most important rules in Philippine inheritance law. Legitimate children’s legitime is protected first. Illegitimate children are also protected, but their shares cannot reduce the legitimate children’s reserved one-half of the estate.

C. Example: Legitimate and Illegitimate Children Survive

Suppose the decedent leaves a net estate of ₱12,000,000, with:

2 legitimate children;
1 illegitimate child;
no surviving spouse.

The legitimate children are collectively entitled to one-half of the estate as legitime:

₱12,000,000 × 1/2 = ₱6,000,000

Each legitimate child’s legitime:

₱6,000,000 ÷ 2 = ₱3,000,000

The illegitimate child’s legitime is one-half of each legitimate child’s legitime:

₱3,000,000 × 1/2 = ₱1,500,000

Total legitime:

Legitimate Child 1: ₱3,000,000
Legitimate Child 2: ₱3,000,000
Illegitimate Child: ₱1,500,000

Total reserved legitime: ₱7,500,000

The balance of ₱4,500,000 is the free portion, subject to testamentary disposition or intestate distribution depending on whether there is a will.

VII. Rights of Legitimate and Illegitimate Children in Testate Succession

A. Testate Succession

Testate succession occurs when the decedent leaves a valid will. The will may distribute the estate, but it cannot impair the legitime of compulsory heirs.

A parent may favor one child over another in a will only within the limits of the free portion. The parent cannot deprive a compulsory heir of legitime unless there is a valid disinheritance.

B. Legitimate Children in Testate Succession

Legitimate children are entitled to their legitime even if the will gives them nothing, gives them less than their legitime, or gives property to other persons.

If the will impairs their legitime, the legitimate children may seek reduction of the testamentary dispositions.

C. Illegitimate Children in Testate Succession

Illegitimate children are likewise entitled to their legitime. A parent cannot simply omit an illegitimate child from a will if that child is legally recognized or can prove filiation.

However, the illegitimate child’s legitime remains limited to one-half of the legitime of a legitimate child, and it cannot prejudice the legitime of legitimate children.

D. Institution of Heirs

A testator may name legitimate or illegitimate children as heirs in a will. The testator may also give them more than their legitime by assigning part or all of the free portion to them.

For example, a parent may leave the free portion to an illegitimate child, provided the legitime of legitimate children and other compulsory heirs is not impaired.

E. Preterition

Preterition occurs when a compulsory heir in the direct line is totally omitted in the inheritance, without being expressly disinherited. In Philippine law, preterition has serious consequences and may annul the institution of heirs.

Preterition is especially relevant when a parent executes a will and completely omits a child. The effects depend on the circumstances, including whether the omitted heir is a compulsory heir in the direct line.

VIII. Rights in Intestate Succession

A. Intestate Succession

Intestate succession occurs when:

The decedent dies without a will;
The will is void;
The will does not dispose of all property;
The heir instituted is incapable of inheriting;
The testamentary dispositions fail for some reason.

In intestacy, the law determines who inherits and in what shares.

B. Legitimate Children in Intestate Succession

Legitimate children are primary heirs. If the decedent leaves legitimate children, they inherit in their own right and generally exclude legitimate parents and ascendants.

If there are multiple legitimate children, they inherit equally.

C. Illegitimate Children in Intestate Succession

Illegitimate children inherit from their parent in intestacy, but their shares are generally smaller than those of legitimate children.

When legitimate children and illegitimate children concur, each illegitimate child generally receives a share equivalent to one-half of the share of a legitimate child, subject to the rules on the surviving spouse and the estate’s distributable portion.

D. Example: Intestate Estate with Legitimate and Illegitimate Children

Suppose a parent dies intestate, leaving:

2 legitimate children;
1 illegitimate child;
no spouse;
net estate of ₱10,000,000.

The ratio is:

Each legitimate child: 2 parts
Each illegitimate child: 1 part

Total parts:

Legitimate Child 1: 2
Legitimate Child 2: 2
Illegitimate Child: 1

Total = 5 parts

Each part = ₱10,000,000 ÷ 5 = ₱2,000,000

Distribution:

Legitimate Child 1: ₱4,000,000
Legitimate Child 2: ₱4,000,000
Illegitimate Child: ₱2,000,000

This illustrates the general intestate rule that an illegitimate child receives one-half of the share of a legitimate child when they inherit together.

IX. Concurrence with the Surviving Spouse

The presence of a surviving spouse affects the distribution of the estate.

A. Legitimate Children and Surviving Spouse

When legitimate children and the surviving spouse survive the decedent, the surviving spouse is also a compulsory heir.

The legitime of the surviving spouse, when concurring with legitimate children, is generally equivalent to the legitime of one legitimate child.

For example, if a decedent leaves two legitimate children and a surviving spouse, the legitimate children collectively receive one-half of the estate as legitime. The surviving spouse’s legitime is equal to that of one legitimate child.

B. Illegitimate Children and Surviving Spouse

Illegitimate children may also concur with the surviving spouse.

The shares vary depending on whether there are legitimate children, legitimate parents, or only illegitimate children and the spouse.

C. Legitimate Children, Illegitimate Children, and Surviving Spouse

When legitimate children, illegitimate children, and the surviving spouse all survive, the computation must respect the following principles:

Legitimate children receive their legitime;
The surviving spouse receives a legitime equivalent to that of one legitimate child;
Illegitimate children receive one-half of the legitime of each legitimate child;
The shares of illegitimate children must not impair the legitime of legitimate children;
The free portion absorbs the shares not charged to the legitime of legitimate children.

D. Example

Assume the decedent leaves a net estate of ₱12,000,000, with:

2 legitimate children;
1 surviving spouse;
1 illegitimate child.

Legitimate children’s collective legitime:

₱12,000,000 × 1/2 = ₱6,000,000

Each legitimate child’s legitime:

₱6,000,000 ÷ 2 = ₱3,000,000

Surviving spouse’s legitime:

₱3,000,000

Illegitimate child’s legitime:

₱1,500,000

Total reserved legitime:

₱6,000,000 + ₱3,000,000 + ₱1,500,000 = ₱10,500,000

Free portion:

₱1,500,000

This free portion may be disposed of by will, subject to the rules on legitime. If there is no will, intestate rules determine its distribution.

X. When There Are No Legitimate Children

A. Illegitimate Children Alone

If the decedent leaves only illegitimate children and no legitimate descendants, legitimate ascendants, or surviving spouse, the illegitimate children may inherit the entire estate by intestacy.

In testate succession, illegitimate children are compulsory heirs and are entitled to their legitime. The remaining free portion may be disposed of by will.

B. Illegitimate Children with Surviving Spouse

If the decedent leaves illegitimate children and a surviving spouse, but no legitimate children or legitimate parents, both the illegitimate children and the surviving spouse inherit.

Their exact shares depend on whether the distribution is by legitime under a will or by intestate succession.

C. Illegitimate Children with Legitimate Parents

If the decedent has no legitimate children but is survived by legitimate parents and illegitimate children, both may have inheritance rights.

The legitimate parents are compulsory heirs in the absence of legitimate children and descendants. Illegitimate children also have legitime. Their respective shares must be computed according to the Civil Code rules.

XI. The Barrier Between Legitimate and Illegitimate Families

A major rule in Philippine succession law is the so-called barrier rule between the legitimate and illegitimate family.

Under the Civil Code, an illegitimate child generally has no right to inherit ab intestato from the legitimate children and relatives of his or her parent. Likewise, legitimate relatives generally do not inherit intestate from the illegitimate child.

This rule is often summarized as a legal barrier between the legitimate family and the illegitimate family.

A. Effect of the Barrier Rule

An illegitimate child may inherit from:

His or her mother;
His or her father, if filiation is established;
His or her own descendants;
In certain cases, other persons who name the child in a valid will.

But the illegitimate child generally does not inherit by intestacy from the legitimate relatives of the parent.

B. Example

Suppose an illegitimate child’s father dies. The illegitimate child may inherit from the father if filiation is established.

But if the father’s legitimate child later dies without descendants, the illegitimate child of the father generally does not inherit by intestacy from that legitimate child as a sibling, because of the barrier between legitimate and illegitimate lines.

XII. Right of Representation

A. Meaning of Representation

Representation is a right created by law where a person steps into the place of another heir who cannot inherit because of predecease, incapacity, or disinheritance.

Representation commonly occurs in the direct descending line. For example, a grandchild may inherit in place of a deceased parent from a grandparent.

B. Legitimate Children and Representation

Legitimate descendants may inherit by representation in proper cases.

For example, if a legitimate child predeceases the parent, the legitimate child’s own children may represent him or her in the inheritance of the grandparent.

C. Illegitimate Children and Representation

Illegitimate children may also have rights of representation, but the rules are more restrictive because of the barrier between legitimate and illegitimate lines.

An illegitimate child can represent his or her parent in the estate of the illegitimate grandparent in appropriate cases, but generally cannot cross into the legitimate family line in intestate succession.

D. Important Limitation

The right of representation does not erase the distinction between legitimate and illegitimate status. Even where representation applies, the share is determined according to the status and legal relationship recognized by law.

XIII. Proof of Filiation

A. Why Filiation Matters

A child cannot claim inheritance rights merely by alleging biological relationship. Inheritance rights depend on legally recognized filiation.

For legitimate children, filiation is usually shown through birth records, marriage records of the parents, or other admissible evidence.

For illegitimate children, proof of filiation is often more contested, especially when the alleged parent has died.

B. Proof of Legitimate Filiation

Legitimate filiation may be proved by:

The record of birth appearing in the civil register;
An admission of legitimate filiation in a public document;
An admission in a private handwritten instrument signed by the parent;
Other evidence allowed by law and jurisprudence, in proper cases.

C. Proof of Illegitimate Filiation

Illegitimate filiation may be established by similar evidence, such as:

Record of birth;
Admission in a public document;
Admission in a private handwritten instrument signed by the parent;
Open and continuous possession of the status of an illegitimate child;
Other evidence allowed by the Rules of Court and jurisprudence.

D. Time Limits

Actions to establish filiation may be subject to prescriptive periods depending on the type of evidence relied upon and the circumstances.

Generally, where the child has strong documentary proof such as a birth record or written admission, the right to claim filiation may be treated differently from cases where the child relies on open and continuous possession of status or other evidence.

Because inheritance claims often arise after death, proof of filiation can become a decisive issue.

XIV. Recognition of Illegitimate Children

A. Recognition Is Important

An illegitimate child’s right to inherit from the father often depends on whether the child was legally recognized or can prove filiation.

Recognition may be voluntary or judicial.

B. Voluntary Recognition

Voluntary recognition may appear in:

The birth certificate;
A public document;
A will;
A private handwritten instrument signed by the parent;
Other legally admissible records.

C. Judicial Recognition

Judicial recognition occurs when a court determines that filiation exists.

This may be necessary when the alleged parent or the legitimate family disputes the relationship.

D. Effect on Inheritance

Once filiation is established, the illegitimate child becomes entitled to inheritance rights as a compulsory heir, subject to the limitations imposed by law.

XV. Surnames and Inheritance Rights

The use of a father’s surname by an illegitimate child is not, by itself, the same as full inheritance recognition in all situations.

Under Philippine law, an illegitimate child may use the surname of the father if the father has expressly recognized the child in accordance with law. However, surname use and inheritance rights still depend on proper proof of filiation.

A birth certificate signed by the father is often significant evidence. But when the father did not sign or acknowledge the child, additional proof may be necessary.

XVI. Disinheritance of Children

A. General Rule

Because legitimate and illegitimate children are compulsory heirs, a parent cannot deprive them of legitime by mere silence, dislike, estrangement, or unequal treatment.

A child may lose legitime only through valid disinheritance or incapacity to inherit.

B. Requirements of Valid Disinheritance

Disinheritance must generally:

Be made in a valid will;
Be for a cause expressly stated by law;
Specify the legal cause;
Be total, not partial;
Be certain and clear;
Not be revoked or reconciled in a manner recognized by law.

A disinheritance made outside a will is generally ineffective.

C. Causes for Disinheritance

The Civil Code provides specific causes for disinheriting children and descendants. These include serious grounds such as maltreatment, refusal to support the parent without justifiable cause, conviction of certain offenses, or attempts against the life of the parent, among others.

A parent cannot invent a ground not recognized by law. For example, “because my child did not visit me often” may not be sufficient unless it falls under a legal cause.

D. Effect of Invalid Disinheritance

If disinheritance is invalid, the compulsory heir is generally restored to his or her legitime.

If a will gives the estate to others while invalidly disinheriting a child, the testamentary dispositions may be reduced to protect the child’s legitime.

XVII. Unworthiness or Incapacity to Inherit

Apart from disinheritance, a child may be barred from inheriting due to unworthiness or incapacity.

Grounds may include serious wrongdoing against the decedent, such as causing or attempting to cause the decedent’s death, making a false accusation of a serious crime, or other grounds under the Civil Code.

Unlike disinheritance, incapacity may operate by law, though it often still requires judicial determination when contested.

XVIII. Donations During Lifetime and Collation

A. Donations May Affect Inheritance

Parents often transfer property to children during their lifetime. These transfers may affect inheritance upon death.

A donation to a compulsory heir may be considered an advance on inheritance unless the donor clearly provides otherwise, subject to legal limits.

B. Collation

Collation is the process of bringing into the hereditary estate certain values received by compulsory heirs during the decedent’s lifetime so that the legitime and shares can be properly computed.

For example, if one legitimate child received a valuable property from the parent during the parent’s lifetime, that donation may need to be considered in computing the child’s inheritance.

C. Donations Cannot Impair Legitime

A parent cannot defeat the legitime of children by donating all property during lifetime. Donations that impair the legitime of compulsory heirs may be reduced after the donor’s death.

This applies whether the affected heir is legitimate or illegitimate, though the amount protected differs.

XIX. The Free Portion

After the legitime of compulsory heirs is satisfied, the remaining part of the estate is called the free portion.

The decedent may dispose of the free portion by will in favor of:

One legitimate child;
One illegitimate child;
The surviving spouse;
A friend;
A charity;
A stranger;
Any person not legally incapacitated to inherit.

A parent may use the free portion to increase the share of an illegitimate child, provided the legitime of legitimate children and other compulsory heirs is not impaired.

XX. Adopted Children

An adopted child generally enjoys the rights of a legitimate child of the adopter for purposes of succession between adopter and adopted child.

This means an adopted child may be a compulsory heir of the adopter and may inherit as a legitimate child from the adopter.

However, adoption affects legal relationships in specific ways. Succession rights between the adopted child and biological relatives may depend on the governing adoption law and the circumstances of the adoption.

In inheritance disputes, the adoption decree and applicable law at the time of adoption are important.

XXI. Children Conceived but Unborn at the Time of Death

A child already conceived at the time of the decedent’s death may have inheritance rights, provided the child is later born under conditions recognized by law.

This protects a posthumous child, whether legitimate or illegitimate, if legal filiation is established.

For example, if a father dies while his wife is pregnant, the unborn legitimate child may be considered in the distribution of the estate once born alive according to legal requirements.

XXII. Waiver or Renunciation of Inheritance

A child may renounce inheritance after the death of the decedent. However, future inheritance generally cannot be waived before death because rights to succession arise only upon death.

A waiver made during the lifetime of the parent may be invalid if it concerns future inheritance.

After death, renunciation must comply with legal formalities, especially if it affects real property or the shares of other heirs.

XXIII. Settlement of Estate

A. Extrajudicial Settlement

If the decedent left no will and the heirs are all of age or properly represented, they may settle the estate extrajudicially under certain conditions.

All heirs, including legitimate and illegitimate children with established rights, must be included. Excluding an heir may make the settlement vulnerable to challenge.

B. Judicial Settlement

Judicial settlement may be necessary when:

There is a will;
There are disputes among heirs;
There are minor heirs;
Filiation is contested;
Estate debts are substantial;
Some heirs refuse to participate;
The estate includes complex property.

C. Partition

Partition is the process of dividing the estate among heirs. Partition may be by agreement or by court order.

A child who is excluded from partition may seek appropriate remedies, subject to prescription, laches, and other defenses.

XXIV. Common Disputes Involving Legitimate and Illegitimate Children

A. Exclusion of Illegitimate Children

A common issue is the exclusion of illegitimate children from estate settlements. Legitimate heirs may deny filiation or claim that the illegitimate child was never recognized.

The illegitimate child must establish legal filiation to inherit.

B. Birth Certificate Issues

A birth certificate may be powerful evidence, especially if signed by the father. But if the father’s signature is absent or disputed, the claimant may need additional evidence.

C. Secret or Unacknowledged Children

Children who were not publicly acknowledged may face difficulty proving filiation, particularly after the alleged parent’s death.

Evidence may include letters, photographs, financial support, school records, insurance records, written admissions, public documents, testimony, and DNA evidence where allowed.

D. Sale of Estate Property Without All Heirs

If some heirs sell estate property without including another compulsory heir, the excluded heir may challenge the sale to the extent of his or her hereditary rights.

Buyers of inherited property must be careful to verify whether all heirs have participated in the sale.

E. Waivers Signed Under Pressure

Some heirs may be asked to sign waivers or quitclaims. A waiver may be challenged if obtained through fraud, mistake, intimidation, undue influence, or lack of proper formalities.

F. Donations Favoring One Child

Parents sometimes donate major properties to one child while alive. Other heirs may later claim that the donation impaired their legitime.

The issue then becomes whether the donation should be collated or reduced.

XXV. Sample Computations

Example 1: One Legitimate Child, One Illegitimate Child, No Spouse

Net estate: ₱6,000,000

Heirs:

1 legitimate child;
1 illegitimate child.

Legitimate child’s legitime:

₱6,000,000 × 1/2 = ₱3,000,000

Illegitimate child’s legitime:

₱3,000,000 × 1/2 = ₱1,500,000

Free portion:

₱6,000,000 − ₱4,500,000 = ₱1,500,000

If there is no will, intestate rules may result in proportional sharing, commonly giving the legitimate child twice the share of the illegitimate child.

Example 2: Two Legitimate Children, Two Illegitimate Children, No Spouse

Net estate: ₱10,000,000

Heirs:

2 legitimate children;
2 illegitimate children.

Intestate ratio:

Each legitimate child: 2 parts
Each illegitimate child: 1 part

Total parts:

2 + 2 + 1 + 1 = 6 parts

Value per part:

₱10,000,000 ÷ 6 = ₱1,666,666.67

Distribution:

Legitimate Child 1: ₱3,333,333.33
Legitimate Child 2: ₱3,333,333.33
Illegitimate Child 1: ₱1,666,666.67
Illegitimate Child 2: ₱1,666,666.67

Example 3: Two Legitimate Children, Surviving Spouse, One Illegitimate Child, With Will

Net estate: ₱20,000,000

Heirs:

2 legitimate children;
surviving spouse;
1 illegitimate child.

Legitimate children’s collective legitime:

₱20,000,000 × 1/2 = ₱10,000,000

Each legitimate child’s legitime:

₱10,000,000 ÷ 2 = ₱5,000,000

Surviving spouse’s legitime:

₱5,000,000

Illegitimate child’s legitime:

₱5,000,000 × 1/2 = ₱2,500,000

Total legitime:

₱10,000,000 + ₱5,000,000 + ₱2,500,000 = ₱17,500,000

Free portion:

₱2,500,000

The testator may give the free portion to any person not legally disqualified. For instance, the will may give the free portion to the illegitimate child, increasing that child’s total share to ₱5,000,000, provided all legitimes are respected.

XXVI. Comparison of Rights

Matter	Legitimate Child	Illegitimate Child
Compulsory heir of parent	Yes	Yes
Legitime	Stronger share	One-half of legitimate child’s legitime
Intestate share when concurring with legitimate children	Full share	One-half of legitimate child’s share
Right to inherit from parent	Yes	Yes, if filiation is established
Right to inherit from legitimate relatives of parent by intestacy	Yes, within legitimate line	Generally barred by the barrier rule
May be given more by will	Yes	Yes, from free portion
May be disinherited	Yes, only for legal cause	Yes, only for legal cause
Must prove filiation	Usually easier through marriage and birth records	Often more contested, especially as to father
Can inherit entire estate if sole heir class	Yes, depending on surviving heirs	Possible if no other preferred heirs and filiation is established

XXVII. Important Civil Code Principles

Several principles are central to understanding the topic:

Compulsory heirs cannot be deprived of legitime except by valid disinheritance.
Legitimate children are preferred over legitimate ascendants.
Illegitimate children are compulsory heirs but receive a smaller share.
Each illegitimate child’s legitime is generally one-half of each legitimate child’s legitime.
The legitime of illegitimate children cannot impair the legitime of legitimate children.
A will cannot override legitime.
Filiation must be legally established.
Illegitimate children generally cannot inherit intestate from the legitimate relatives of their parents.
Donations during lifetime may be reduced if they impair legitime.
Estate settlements must include all heirs with legally recognized rights.

XXVIII. Practical Checklist for Children Claiming Inheritance

A child claiming inheritance should determine:

Whether the decedent left a will;
Whether the estate has been settled;
Whether the claimant is legitimate, legitimated, adopted, or illegitimate;
Whether filiation is documented;
Whether there are other compulsory heirs;
Whether estate properties were sold, donated, or transferred;
Whether the claimant was excluded from an extrajudicial settlement;
Whether any waiver was signed;
Whether the claim has prescribed or is affected by laches;
Whether judicial settlement or an action to establish filiation is necessary.

XXIX. Practical Checklist for Estate Planning

A parent who wants to plan inheritance should consider:

Identifying all compulsory heirs;
Determining which children are legitimate, illegitimate, legitimated, or adopted;
Preparing a valid will if unequal distribution is intended;
Respecting the legitime of all compulsory heirs;
Properly documenting donations;
Avoiding transfers that may later be attacked as impairing legitime;
Clearly recognizing children where legally intended;
Keeping civil registry records accurate;
Considering estate taxes and settlement expenses;
Avoiding informal arrangements that may later create disputes.

XXX. Conclusion

Philippine inheritance law protects both legitimate and illegitimate children, but it does not treat them equally. Legitimate children have a preferred position and receive a larger legitime and intestate share. Illegitimate children are also compulsory heirs, but their legitime is generally limited to one-half of the legitime of a legitimate child, and their inheritance rights are subject to the requirement of proving filiation and to the barrier between legitimate and illegitimate family lines.

The most important point is that a parent cannot freely disregard compulsory heirs. Whether a child is legitimate or illegitimate, the law reserves a portion of the estate for that child, subject to the specific rules on legitime, disinheritance, incapacity, and proof of filiation.

In actual inheritance disputes, the outcome often depends not only on the child’s status but also on the existence of a will, the presence of a surviving spouse or other heirs, prior donations, documentary proof, estate settlements, and whether the child’s filiation has been legally established.