I have adopted 3 minor special-needs sons, over 11 years working with Children Services. During those years, I never found a girl that was available for adoption that would be safe for my boys. I am MOM to 4 special-needs boys, 19-30 years old, that will never be able to leave home, get married, have children, etc. My boys are my LIFE. They have always wanted a sister and I have always wanted a daughter. By the time I was of age, I was an orphan. It would have been nice to have parents and my children have grandparents. 🙂
Ohio does permit adopting an adult under certain circumstances. The adoption must be approved by the court and you will be carefully checked out before it is permitted. Read the regulations on the website linked below.
That would be called a wife.