19 GCA § 9106: By Will.

A guardian of the person or estate, or of both, of a child born, or likely to be born, may be appointed by will or by deed, to take effect upon the death of the parent appointed:

(a) If the child be legitimate, by either parent, with written consent of the other; or by either parent, if the other be dead or incapable of consent.

(b) If the child be illegitimate, by the mother: Provided further, that any parent may, by deed or will, appoint a guardian as to the property which his or her child may inherit and take by devise or bequest from him or her.