Ohio Revised Code Title XXI. Courts Probate Juvenile § 2111.12

(A) A minor over the age of fourteen years may select a guardian who shall be appointed if a suitable person. If a minor over the age of fourteen years fails to select a suitable person, an appointment may be made without reference to the minor's wishes. The minor shall not select one person to be the guardian of the minor's estate only and another to be the guardian of the person only, unless the court that appoints the guardian is of the opinion that the interests of that minor will be promoted by that selection.

(B) A surviving parent by a will in writing may appoint a guardian for any of the surviving parent's children, whether born at the time of making the will or afterward, to continue during the minority of the child or for a less time.

When the father or mother of a minor names a person as guardian of the estate of that minor in a will, the person named shall have preference in appointment over the person selected by the minor. A person named in that will as guardian of the person of that minor shall have no preference in appointment over the person selected by the minor, but in that event the probate court may appoint the person named in the will, the person selected by the minor, or some other person.

Whenever a testamentary guardian is appointed, the testamentary guardian's duties, powers, and liabilities in all other respects shall be governed by the law regulating guardians not appointed by will.

(C) A parent pursuant to a durable power of attorney under section 1337.24 or a writing as described in division (A) of section 2111.121 of the Revised Code may nominate a person to be a guardian for one or more of the parent's minor children, whether born at the time of the making of the nomination or afterward.