Legal Definitions - fertile-octogenarian rule

The fertile-octogenarian rule is a historical legal principle that, for specific purposes related to property law, assumed an individual (typically a woman) was capable of having children regardless of their age or physical condition. This legal fiction was primarily applied in the context of the Rule Against Perpetuities, a complex legal doctrine designed to prevent property from being tied up indefinitely in the future without clear ownership.

The Rule Against Perpetuities requires that all interests in property must vest (meaning ownership becomes certain) within a specific period after the death of someone alive when the interest was created, plus 21 years. The fertile-octogenarian rule complicated this by hypothetically extending the possibility of new heirs being born far into the future, potentially causing property interests to violate the perpetuity period.

While largely considered outdated today, this rule meant that even a very elderly person was legally presumed capable of having another child, which could theoretically delay the final vesting of property ownership beyond the permissible timeframe. Most modern legal systems have abandoned or significantly modified this rule, often by setting reasonable age limits for fertility or by adopting a "wait-and-see" approach to determine if a perpetuity violation actually occurs.

Here are some examples illustrating how the fertile-octogenarian rule would have applied:

• Example 1: A Trust for Future Grandchildren

  Consider a will that establishes a trust, stating: "My property shall be held in trust for my grandchildren, and the principal distributed to the last grandchild to reach the age of 25."

  • How it illustrates the rule: If the testator (the person making the will) had a child who was still alive and, under the fertile-octogenarian rule, considered capable of having another child at any age, this could create a problem. Even if the testator's existing children were elderly, the rule would assume they could have another child. This hypothetical "new" child would then have to reach age 25, potentially pushing the final distribution of the trust principal far beyond the time allowed by the Rule Against Perpetuities. The uncertainty of when this "last grandchild" might be born and reach 25 would make the trust invalid under the strict application of the perpetuity rule.

• Example 2: Conditional Inheritance for Descendants

  Imagine a will that leaves a large estate to "my descendants who are alive 21 years after the death of my last surviving child."

  • How it illustrates the rule: If the testator's last surviving child was, say, 85 years old, the fertile-octogenarian rule would still legally presume that this 85-year-old child could have another child. This hypothetical new child would then become the "last surviving child" for the purpose of the will. The 21-year period would then start counting from the death of this hypothetical child, who could be born decades later. This scenario would make it impossible to determine with certainty who the beneficiaries would be within the required perpetuity period, thus potentially invalidating the gift under the Rule Against Perpetuities.

• Example 3: Property to the "First Great-Grandchild Born After a Specific Date"

  Suppose a will states: "My summer home shall pass to the first great-grandchild born after January 1, 2070."

  • How it illustrates the rule: If the testator's child is still alive when the will takes effect, and that child is considered fertile regardless of age, they could theoretically have another child. This new child could then have a child (the great-grandchild) at a much later date than if fertility were assumed to end at a reasonable age. The fertile-octogenarian rule would force the court to consider this remote possibility, potentially making it impossible to determine who the "first great-grandchild born after January 1, 2070" would be within the perpetuity period, thereby invalidating the gift of the summer home.