The importance of belonging to a family does not stop at 18, and the joys of adoption do not end at 18 either. There are many life stories that lead to adult adoption, when a person over the age of 18 is adopted by another adult. Adult adoption often occurs when a child in foster care ages out of the system or when a stepchild wants to memorialize the relationship with their stepparent.
Common Reasons Families Pursue Adult Adoption
Every family that comes to us for an adult adoption has its own story. A young adult who aged out of foster care may want the legal permanence that never came earlier in life. A stepparent who raised a child through their formative years may want to make that bond legally official, especially once the pressures of a custody arrangement are no longer in play. We’ve also worked with families pursuing adult adoption to formalize a long-term caregiving relationship, or to make sure inheritance and estate matters reflect the family as it actually exists. Whatever the reason, the goal is usually the same: making a relationship that already feels like family legally recognized as one.
Missouri Requirements for Adult Adoption
Adult adoptions require fewer documents and tasks than child adoptions. While a child adoption requires a home study and usually biological parental notice and consent, a Missouri adult adoption doesn’t require either. The adult adoption petition is filed along with only a few supporting documents, such as an affidavit of expenses. The key requirement is the adult adoptee’s own consent, which must be filed with the court along with everything else.
What Happens at the Adoption Hearing
Once the necessary documents are filed with the court, the case is set for a hearing date. At the hearing, the attorney asks questions of the prospective parent or parents and of the adult adoptee. These questions center on the relationship between them and on the adoptee’s consent and desire to be adopted. When the judge is satisfied, they enter an order of decree of adoption, the legal document that finalizes the adoption.
After the Adoption Is Finalized
Once the decree is entered, the adoptee’s birth certificate is amended to reflect the adoptive parents. Legally, the adoptee becomes the adoptive parent’s child in every sense that matters, including inheritance rights, the same as if they had been born into the family. Families sometimes need to update other documents after the adoption, such as wills, trusts, and beneficiary designations, so the paperwork matches the relationship the adoption just made official.
Frequently Asked Questions
Does adult adoption affect inheritance rights in Missouri?
Yes. Once finalized, the adoptee has the same inheritance rights as a biological child of the adoptive parent, and often loses inheritance rights from their biological parents unless the court specifies otherwise.
Can a stepparent adopt an adult stepchild in Missouri?
Yes, this is one of the most common reasons families pursue adult adoption, and it does not require the consent of the child’s other biological parent.
Will the adoptee’s name or birth certificate change?
The birth certificate is amended to reflect the adoptive parents. A name change can be requested as part of the same proceeding if the family wants one.
Do biological parents need to be notified or give consent?
No. Unlike a child adoption, an adult adoption does not require notice to or consent from the adoptee’s biological parents. The adoptee’s own consent is what matters.
Talk to an Adoption Attorney in Missouri
No matter the circumstances that lead adults to pursue adoption of a person over the age of 18, an adoption attorney can help you and your family through the process. Contact an experienced adoption attorney at Paule, Camazine & Blumenthal for your family formation needs.
*This blog was written with the assistance of Caroline Vaaler, Saint Louis University Law School 2026 graduate.
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