Adult adoption in Missouri is a streamlined court process: you file a petition in the juvenile division of the circuit court, the adult you are adopting signs a written consent, and after a short hearing the judge issues a decree that makes the adoptee your legal child for every purpose, including inheritance. No home study, no agency, no termination of anyone else’s parental rights beforehand. The consent of the adult being adopted is, by statute, enough on its own.
Who Can Adopt and Whose Consent Is Needed
Section 453.010 says “any person desiring to adopt another person as his or her child” may file a petition with the circuit court.1Missouri Revisor of Statutes. Missouri Revised Statutes 453.010 – Petition for Permission to Adopt, Venue, Jurisdiction The statute sets no minimum age for the adopter and no maximum age for the adoptee. Courts expect the adopter to be an adult, but the text simply says “any person.”
The consent rule is what makes adult adoption so much lighter than adopting a child. Section 453.030 provides that when the person being adopted is eighteen or older, “his or her written consent alone to his or her adoption shall be sufficient.”2Missouri Revisor of Statutes. Missouri Revised Statutes 453.030 – Approval of Court No biological parent has to sign. No agency has to weigh in. The adult adoptee agrees in writing, and that satisfies the statute.
If you are married, pay attention to spousal joinder. A living, competent spouse may join in the petition, and the court can order your spouse to join. If that order is ignored, the case can be dismissed.1Missouri Revisor of Statutes. Missouri Revised Statutes 453.010 – Petition for Permission to Adopt, Venue, Jurisdiction If you plan to adopt an adult without your spouse joining, expect the court to ask why.
Where and How to File the Petition
File in the juvenile division of the circuit court. Don’t let the name throw you: Missouri routes all adoption petitions through the juvenile division regardless of the adoptee’s age. Venue is proper in the county where you live or the county where the adoptee is located when you file.1Missouri Revisor of Statutes. Missouri Revised Statutes 453.010 – Petition for Permission to Adopt, Venue, Jurisdiction
The petition identifies both parties, explains the relationship, and states the reasons for the adoption. The adult adoptee’s written consent gets filed with the court.2Missouri Revisor of Statutes. Missouri Revised Statutes 453.030 – Approval of Court Many circuits publish standardized adult adoption forms, so ask the clerk of your county before drafting from scratch. Filing fees generally run in the range of roughly $200 to $300 depending on the county.
What Happens at the Hearing
Once the petition is on file, the court sets a hearing. Under Section 453.080 the judge has to find that “it is fit and proper that such adoption should be made.”3Missouri Revisor of Statutes. Missouri Revised Statutes 453.080 – Hearing, Decree For an adult adoption, that inquiry is narrow. The judge confirms the adoptee consented voluntarily, that no fraud or improper purpose is in play, and that granting the decree is appropriate.
Most of the heavier requirements in Section 453.080 don’t apply here. The six months of prior custody, postplacement assessments, guardian ad litem recommendations, and Interstate Compact on the Placement of Children compliance are all directed at adoptions of minors.3Missouri Revisor of Statutes. Missouri Revised Statutes 453.080 – Hearing, Decree There is no home study, no criminal background check, no social worker investigation. If consent is clear and the purpose is legitimate, judges often grant the decree the same day.
What the Decree Actually Changes
Once the court signs the decree, the adopted adult is legally your child “for every purpose … as fully as though born to [you] in lawful wedlock.” That language comes from Section 453.090, and subsection 5 defines “child” in the adoption chapter to include people over eighteen.4Missouri Revisor of Statutes. Missouri Code 453.090 – Consequences of Adoption, Child Defined
Inheritance changes in both directions. The adoptee can inherit from you under Missouri’s intestate succession rules, the same way a biological child would, and you can inherit from the adoptee.4Missouri Revisor of Statutes. Missouri Code 453.090 – Consequences of Adoption, Child Defined The probate code carries the same rule: “an adopted person is the child of an adopting parent” for purposes of intestate succession.5Missouri Revisor of Statutes. Missouri Code 474.060 – Adopted Persons The adoptee also gains the right to inherit property specifically limited to “heirs of the body” of the adoptive parent, language that still appears in some older trusts and deeds.
Ties to Biological Parents End
This is the piece that catches some people off guard. Under Section 453.090, once the decree is entered, “all legal relationships and all rights and duties” between the adoptee and their biological parents end.4Missouri Revisor of Statutes. Missouri Code 453.090 – Consequences of Adoption, Child Defined That includes the right to inherit from those biological parents. Under Missouri’s intestate rules, the adopted person is no longer treated as the child of their natural parents for inheritance purposes.5Missouri Revisor of Statutes. Missouri Code 474.060 – Adopted Persons
There is one important exception. If a biological parent joins in the adoption petition, as happens in stepparent adoptions, that biological parent’s legal relationship with the adoptee survives.4Missouri Revisor of Statutes. Missouri Code 453.090 – Consequences of Adoption, Child Defined So when a stepfather adopts his adult stepchild and the biological mother joins the petition, the child keeps the legal relationship with the mother and gains one with the stepfather. The legal relationship with the other biological parent is still severed.
Personal relationships aren’t governed by statute, of course. The adoption changes the legal architecture, not the family you spend holidays with. But the inheritance trade-off is worth understanding clearly before you file.
Adopting an Adult Who Cannot Consent
The simplified consent rule runs into a wall when the adult being adopted lacks the mental capacity to consent. Section 453.030 requires written consent from anyone fourteen or older being adopted, “except where the court finds that such child has not sufficient mental capacity to give the same.”2Missouri Revisor of Statutes. Missouri Revised Statutes 453.030 – Approval of Court The statute uses “child,” but Section 453.090 confirms that “child” in this chapter means a person of any age.4Missouri Revisor of Statutes. Missouri Code 453.090 – Consequences of Adoption, Child Defined
Where an adult cannot consent because of a disability, the court may appoint a guardian ad litem to represent the adoptee’s interests. Under Section 475.097, a guardian ad litem has only the authority spelled out in the appointment order, and the incapacitated person’s reasonable expenses along with the guardian ad litem’s compensation can be taxed as costs of the proceeding.6Missouri Revisor of Statutes. Missouri Code 475.097 – Conservator or Guardian Ad Litem, Conflicts of Interest, Removal Expect more court scrutiny and a longer timeline than a routine adult adoption.
Updating the Birth Certificate
After the decree issues, the clerk of the court sends a Certificate of the Decree of Adoption to the Missouri Department of Health and Senior Services, Bureau of Vital Records. That certificate lists the adoptee’s original name, new name, sex, date and place of birth, names of biological parents if known, and names of the adoptive parents.7Missouri Revisor of Statutes. Missouri Code 453.100 – Certificate of Decree to Department of Health
The Bureau of Vital Records then prepares a new birth certificate showing the adoptive parents. Processing the Certificate of Decree of Adoption costs $15, and a copy of the new birth certificate costs another $15. Payment is by check or money order to the Missouri Department of Health and Senior Services, sent to the Bureau of Vital Records at 930 Wildwood Drive, Jefferson City, MO 65109.8Missouri Department of Health and Senior Services. Correct/Amend a Vital Record
If the decree includes a name change, the new birth certificate reflects the new name. Use the new birth certificate and the adoption decree to update Social Security, driver’s license, passport, and other identification.
What Adult Adoption Does Not Unlock Federally
Adult adoption creates a legal parent-child relationship under Missouri law, but federal agencies apply their own eligibility rules, and most limit “child” benefits to minors or to adults with disabilities. Knowing this upfront prevents surprises.
The federal adoption tax credit is available only for adopting someone who is either under eighteen or physically or mentally incapable of self-care.9Internal Revenue Service. Adoption Credit Adopting a healthy adult does not qualify.
The Department of Veterans Affairs recognizes adopted children as dependents only if the child is under eighteen, is between eighteen and twenty-three and enrolled in school, or became permanently disabled before turning eighteen.10Veterans Affairs. Manage Dependents for Disability, Pension, or DIC Benefits An adult adoptee outside those categories will not be added as a dependent for VA disability or pension purposes.
Social Security follows the same pattern. An adopted adult may qualify for benefits on the adoptive parent’s record only if they have a disability that began before age twenty-two; otherwise the standard child-beneficiary cutoffs apply. Adoption by itself does not create a new Social Security entitlement for a healthy adult adoptee.
The state-law benefits — inheritance, next-of-kin status, formal recognition of a family bond — are real and durable. Federal benefits mostly aren’t part of the package.
Common Reasons People Pursue Adult Adoption
Stepparent adoption is the most common scenario. A stepparent who raised a child from a young age often wants to formalize that bond after the child turns eighteen, especially if the adoption was never completed during minority. Because only the adult adoptee’s consent is required, there is no need to locate a biological parent who has been absent for years.
Inheritance planning drives many adult adoptions. Adopting an adult gives that person a legal claim to inherit as your child, which can be simpler and harder to challenge than a will alone. Wills get contested; the parent-child relationship created by adoption is much harder to attack.
Caregiving relationships are another common motivation. When an adult has been cared for by someone other than a biological parent, such as a grandparent, aunt, or long-time family friend, adoption formalizes that reality and gives the caregiver next-of-kin status for hospital visitation and medical decision-making.
Before You File
Adult adoption in Missouri is legally permanent. There is no simple mechanism to undo it if the relationship later sours. Courts can vacate adoptions in limited circumstances, but it is not a routine process and there is no guarantee a judge will agree.
Think carefully about the severing of biological family ties. Even if you have no active relationship with a biological parent now, the adoption ends your legal right to inherit from that parent if they die without a will. Where a biological parent has significant assets and no estate plan, that trade-off deserves real thought.
Plenty of people handle adult adoptions without a lawyer, and the filing itself is straightforward. Consulting one is still worthwhile if the adoptee lacks capacity, if inheritance implications are complex, or if existing trusts might be affected by adding a new legal child to your family. An hour with a family law attorney before filing can head off much bigger problems later.