Adoption is the same legal process whether the individual is a child or an adult. The court issues a new birth certificate for the adopted individual and any existing legal relationships with biological or custodial parents are severed. The adopted adult can change his or her last name, also called a surname change, and all adoption records will be sealed.The second reason, almost as common, is to formalize an existing parent/child relationship. For example, parents can adopt a now adult foster child or stepchild. Adult adoption is a popular option for biological parents as well as for children who find their birth family and wish to be formally acknowledged or fathers who find children they didn't know they had.Finally, adult adoptions often occur to provide perpetual care for an adult who has a diminished capacity or disability. Such adult adoptions can assume responsibility for a mentally disabled or challenged individual, or someone who is physically disabled. Through the adoption process, one adult can become the responsible party and decisionmaker for another adult's care.