Short answer. Article 5 bars marriage to anyone under the impediments in Articles 37 and 38. Article 37 voids marriages between ascendants and descendants and between siblings; Article 38 voids marriages between certain relatives by blood, affinity, or adoption, and between a person and the spouse of someone they killed to marry the other.

What the law says

Any male or female of the age of eighteen years or upwards not under any of the impediments mentioned in Articles 37 and 38, may contract marriage.

Family Code, Article 5 — Legal Capacity to Marry. Read the full provision →

What the law says

Marriages between the following are incestuous and void from the beginning, whether relationship between the parties be legitimate or illegitimate: (1) Between ascendants and descendants of any degree; and (2) Between brothers and sisters, whether of the full or half blood.

Family Code, Article 37 — Incestuous Marriages. Read the full provision →

What the law says

The following marriages shall be void from the beginning for reasons of public policy: (1) Between collateral blood relatives whether legitimate or illegitimate, up to the fourth civil degree; (2) Between step-parents and step-children; (3) Between parents-in-law and children-in-law; (4) Between the adopting parent and the adopted child

Family Code, Article 38 — Marriages Void for Public Policy. Read the full provision →

Article 5 sets age plus a cross-reference to two other articles

Article 5 gives the basic rule for who may marry: "any male or female of the age of eighteen years or upwards not under any of the impediments mentioned in Articles 37 and 38, may contract marriage." Age alone is not enough. Even an adult of legal age cannot validly marry if the relationship between the two people falls under one of the impediments those two articles list, since those impediments exist independently of age.

Article 37: incestuous marriages

Article 37 voids marriages that the law calls incestuous "whether relationship between the parties be legitimate or illegitimate" — meaning it does not matter whether the family relationship arose from a valid marriage or not. It covers marriages "between ascendants and descendants of any degree," which reaches parents, grandparents, children, and grandchildren without limit, and marriages "between brothers and sisters, whether of the full or half blood," covering siblings who share one parent as well as both.

Article 38: marriages void for public policy

Article 38 lists a broader set of relationships the law voids for reasons of public policy rather than blood alone. It includes marriage "between collateral blood relatives whether legitimate or illegitimate, up to the fourth civil degree" — reaching relatives like first cousins — and extends to relationships created by marriage or adoption, such as "between step-parents and step-children" and "between parents-in-law and children-in-law." It also voids marriage between an adopting parent and the adopted child, and among certain relatives connected through adoption.

Why these impediments matter beyond the ceremony itself

A marriage that falls under either article is void from the very beginning, not merely voidable — it never produced a valid marital relationship at all, regardless of how properly the ceremony itself was performed or how sincerely both parties intended to marry. This affects property relations, legitimacy of any children, and inheritance rights, because the law treats the union as if the marriage never legally existed. Anyone facing a question about whether a particular family relationship falls within these impediments should look closely at exactly how the two people are related, since the degree and type of relationship is what the law turns on.

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.

Related provisions

Note. Statute text quoted on this page is reproduced from the official enactment and is linked to the full provision. The explanation around it is general legal information from Vivas & Nobles Law Office, not legal advice. Whether it applies to your situation depends on facts only a lawyer reviewing them can assess.