TV dramas often portray plots where the mistress gets pregnant and gives birth to an illegitimate child, tearing a family apart. When this happens in real life, there are even more troublesome issues to deal with, such as the recognition of non-marital children and inheritance disputes involving illegitimate children. This article will help you understand the legal definition of an illegitimate child and how to prevent them from claiming inheritance, while also explaining how such children can protect their own rights.

Legal Definition of Illegitimate Child — Understanding Non-Marital Children Under Civil Law

When people hear the term "illegitimate child," they often think of a child born from a husband’s affair with another woman. However, the correct legal term is "non-marital child."

According to Article 1061 of the Civil Code of Taiwan:

“A child born during a valid marriage is deemed a legitimate child.”

From this, we understand the definition of a marital child. But what about non-marital children? Here are two examples to help clarify the concept.

• Recognition and Legitimation of Non-Marital Children

  Jimmy and Amy met and fell in love during college. They dreamed of getting married after graduation, but when Amy told Jimmy she was pregnant, his reaction wasn’t what she had hoped for. Jimmy said he wasn’t ready for marriage, and the disappointment led Amy to break up with him, although she couldn’t bring herself to terminate the pregnancy.

  Although non-marital children aren’t immediately entitled to the same legal care from both parents as marital children, Article 1065 of the Civil Code states:

  “The relationship between a non-marital child and the birth mother is treated the same as that of a marital child, and recognition is not required.”

  Additionally, the Civil Code provides a system for biological fathers and children to establish a legal relationship through “legitimation” and “recognition.”

  • Legitimation: According to Article 1064, if the biological parents of a non-marital child marry each other, the child is considered a marital child.
  • Recognition: Under the Civil Code, this is when the biological father acknowledges a non-marital child as his own, granting the child the same legal status as a marital child. If the father provides care and support, the child is legally deemed recognized, even without formal declaration.
• Denial of Non-Marital Child Status

  Wen-Chun and Jing-Xiang had been married for 10 years when their relationship deteriorated. During a heated argument, Jing-Xiang finally confessed a long-hidden secret — their son was not actually Wen-Chun’s child.

  Faced with this devastating truth after raising the child for over a decade, Wen-Chun wondered if he was still obligated to continue parenting.

The answer is no. Article 1063 of the Civil Code stipulates:

“A child conceived during a valid marriage is presumed to be the child of the husband.”

However, this presumption can be overturned. The same article states:

“Either spouse or the child may file a suit to deny paternity if it can be proven that the child is not a marital child.”

In this case, Wen-Chun can conduct a DNA test to confirm the absence of a biological relationship and then file a “paternity denial lawsuit.” The court will make a final judgment on the matter.

Inheritance Disputes Involving Illegitimate Children — Understanding Legal Concepts of Recognition and Inheritance Rights

After 15 years of marriage, Bing-Hu’s wife, Ah-Fu, noticed his suspicious behavior and hired a private investigator, only to discover that Bing-Hu had been supporting an illegitimate child for several months.

But do illegitimate children have inheritance rights under the law? The answer is yes — but not unconditionally. The biological father must legally recognize the child, either through voluntary recognition or court-ordered recognition.

Here’s how the two pathways work:

• Compulsory Recognition: A non-marital child or their mother may file a lawsuit requesting the court to declare the child as the biological child of the father. If the father is deceased, the child can sue his legal heirs. If no heirs exist, the social welfare authorities or the prosecutor will be appointed as defendants.
• Voluntary Recognition: If the father openly acknowledges the child, whether verbally or in writing, this is considered recognition under the law. Additionally, if the child can prove the father provided financial support or care, this is also treated as legal recognition, even without formal acknowledgment.

Once recognized, the non-marital child is legally treated the same as a marital child, including full inheritance rights.

How to Prevent Illegitimate Children from Claiming Inheritance

As explained above, once a non-marital child is recognized, they have the same inheritance rights as a marital child. Therefore, if you want to prevent this, you must take action while the father is still alive.

Before planning, it’s essential to understand two key legal terms under the Civil Code:

• Statutory Share: The portion of an estate calculated based on the number of heirs. For example, if there are three first-order heirs, each is entitled to one-third of the estate.
• Reserved Portion (Legitime): The minimum portion of inheritance that the law guarantees to heirs, even against the wishes of the deceased. For direct descendants and parents, it is half of the statutory share; for siblings and grandparents, it is one-third.

According to Article 1138, the order of statutory heirs is:

• Direct descendants (children, grandchildren, etc.)
• Parents
• Siblings
• Grandparents

Two Ways to Prevent Non-Marital Children from Inheriting

• Making a Will: While the law protects a non-marital child’s reserved portion, the testator can limit their share by reducing the rest of their inheritance. If the child has committed serious misconduct — like fraud, coercion, or forgery of a will — they may be disqualified from inheriting.
• Transferring Assets: The father can transfer assets to the spouse or legitimate children while still alive. This is a common way to avoid inheritance disputes. Planning ahead is crucial, as large transfers close to death may be reclassified as part of the estate and subject to inheritance tax. Transferring assets gradually through annual gifts or purchasing real estate for children are common strategies.

Other techniques include depleting assets, using life insurance for wealth transfer, or gifting assets directly. Consulting a professional attorney is highly recommended for the most effective planning. However, these methods all require the father’s consent — if the father is determined to leave assets to the illegitimate child, it is nearly impossible to prevent.

(Further Reading: What to Do If Your Partner Is Cheating? Learn How to Defend Yourself Against Family Interference and Protect Your Rights with Solid Evidence!)

Tackle the Illegitimate Child Issue at Its Root — With Yi-Tong Private Investigation Agency

If you want to prevent an illegitimate child from tearing your family apart or fighting over inheritance, the best approach is early detection and prevention of extramarital affairs. Just like doctors say: prevention is better than cure. If you can detect signs of infidelity early, you won’t have to worry about illegitimate children, legal recognition, or inheritance disputes later on.

Yi-Tong Investigation Agency has over 40 years of experience in the industry and can provide you with professional and comprehensive evidence-gathering services to help you uncover your partner’s infidelity, and eliminate the root of the illegitimate child problem.