California Posthumous Heirs: Inheritance Rules Explained

Diagram summarising posthumous heirs California under California and federal law — Visual summary of posthumous heirs California

What Happens When a Child Is Born (or Conceived) After a Parent Dies?

California’s inheritance rules were written for the ordinary case: a parent dies, and the children who were already alive inherit. But biology and modern medicine don’t always cooperate with that timeline. California law recognizes two very different situations involving posthumous heirs, and the California Bar Exam loves to test the difference between them.

If you’re studying for the California Bar Exam, or you’re simply trying to understand your family’s inheritance rights after a death, this guide breaks down both doctrines in plain terms — with the exact Probate Code sections you need.

The Two Doctrines, Defined

A posthumous child is a child conceived during the decedent’s lifetime but born after death. This child is treated as if born during the decedent’s life, so long as the child is later born alive — no consent or paperwork from the deceased parent is required.

A posthumously conceived child is conceived after death, using the decedent’s stored genetic material (sperm, eggs, or embryos). Because the decedent can no longer confirm intent at the moment of conception, California imposes a much stricter, consent-driven test before this child can inherit.

Posthumous Children: Probate Code § 6407

California Probate Code § 6407 governs the first scenario. A child who was “in gestation” at the decedent’s death is treated as living at the moment of death, provided the child is later born alive.

Section 6407 gives claimants two ways to prove gestation at death:

The 280-day presumption. If the child is born within 280 days after the relevant date, gestation at that time is presumed.
Clear and convincing evidence. Outside the 280-day window (for example, a longer or medically complicated pregnancy), the claimant can still prove gestation at death with clear and convincing evidence.

No written authorization is required, because conception happened while the decedent was alive — the decedent’s own choice to conceive supplies the necessary intent. The posthumous child inherits under the normal intestate succession rules, sharing equally with the decedent’s other children.

Posthumously Conceived Children: Probate Code § 249.5

This is where things get technical. Assisted reproduction now lets a surviving partner conceive a child years after a person’s death, using frozen genetic material. California Probate Code § 249.5 addresses the obvious risk: how do you know the decedent actually wanted to become a parent this way, and wanted to support the resulting child financially?

The statute answers with four mandatory conditions, all of which must be proven by clear and convincing evidence:

Condition	What it requires
1. Written consent	Decedent specified in writing, signed and dated, that genetic material could be used for posthumous conception, named a specific person to control its use, AND consented to support the resulting child
2. Timely notice	The person controlling the genetic material gave written notice to the estate representative within 4 months of the death certificate’s issuance
3. Two-year window	The child must be in utero, using the decedent’s genetic material, within 2 years of the date on the death certificate
4. Burden of proof	Every condition above must be proven by clear and convincing evidence

Miss even one condition, and the posthumously conceived child does not qualify as an heir. There is no “close enough” exception — not for late notice, not for a missing signature, not for conception that happens even a few months past the two-year cutoff.

A Worked Example

Let’s put this into a hypothetical, the kind you’d see on the California Bar Exam.

Maria and David were engaged when David, age 34, learned he had testicular cancer requiring chemotherapy that would likely leave him infertile. Before treatment, David banked sperm and signed a written document naming Maria as the person authorized to use it after his death, expressly stating he wanted any resulting child supported from his estate. David died eight months later from complications unrelated to the cancer.

Maria notified David’s estate administrator in writing three months after his death certificate issued — within the four-month window. She conceived via IVF using David’s stored sperm fourteen months after the death certificate date — within the two-year window. Their daughter, Sophia, was born the following year.

Analysis: All four § 249.5 conditions are met: written consent to both use and support, timely notice, conception within two years, and (presumably) proof by clear and convincing evidence. Sophia qualifies as David’s heir and is treated as “born” at David’s death for succession purposes — including any omitted-child claims against a prior will.

Now change one fact: suppose Maria never received a signed writing from David, only his verbal wish expressed to his oncologist. Even if everyone believes David truly wanted this, oral authorization does not satisfy § 249.5. Sophia would not qualify as David’s legal heir under this doctrine.

Why California Draws This Line

The gap between these two doctrines reflects a real policy tension. A posthumous child under § 6407 was already on the way before death — the decedent’s intent to become a parent is baked into the biology. A posthumously conceived child under § 249.5 exists only because someone else made a decision after the decedent could no longer weigh in. Without strict, written safeguards, estates could face inheritance claims from children conceived years — even decades — after death, using genetic material the decedent may not have wanted used that way, or at all.

That’s why § 249.5 layers on a written-consent requirement, a notice deadline, a conception window, and a heightened evidentiary standard, while § 6407 asks only whether gestation had already begun.

How This Interacts With Other Succession Rules

If a posthumously conceived child qualifies under § 249.5, that child is treated as “born” at the decedent’s death for essentially every succession purpose. That means the child can:

Claim omitted-child protection against a will executed before the child’s conception (Probate Code §§ 21620–21623).
Claim omitted-heir protection against a revocable trust.
Share equally in intestate property with the decedent’s other children.

Estate planners routinely advise clients who bank genetic material to sign a clear, dated written authorization now, rather than leave the question to a court years later.

FAQ

Does a posthumous child need a DNA test to inherit in California?

Not automatically. The claimant must prove gestation at the decedent’s death, either through the 280-day presumption or clear and convincing evidence. DNA testing is common evidence in contested cases but isn’t a separate statutory requirement under § 6407.

Can a posthumously conceived child inherit if the decedent left no will?

Yes, if all four § 249.5 conditions are satisfied, the child inherits through intestate succession just like any other child, sharing equally with siblings.

What if the written consent exists but notice was given five months after the death certificate issued?

The claim fails. Probate Code § 249.5 sets a strict four-month notice deadline with no equitable exception for late filing, even by a short margin.

Key Takeaways

Posthumous children (conceived before death, born after) inherit under Probate Code § 6407 based on gestational timing alone — no consent required.
Posthumously conceived children (conceived after death using stored genetic material) must satisfy all four conditions of Probate Code § 249.5: written consent to use and support, timely notice, a two-year conception window, and clear and convincing proof.
These are separate doctrines with separate tests; don’t apply one statute’s rule to the other’s fact pattern.
On the California Bar Exam, treat the four § 249.5 conditions as an independent checklist — examiners often plant a single missing element to test whether you catch that all four are mandatory.
Anyone banking genetic material should execute a clear, signed, dated written authorization now to avoid future disputes.

This article is educational and is not legal advice. Consult a licensed California attorney about your situation.