The wage earner, Alfredo H. M~, filed an application for child's insurance benefits
                  on January 18, 1982, on behalf of Mehlanie M~. Mehlanie was born in the Philippines
                  on November 2, 1974, to Marita M~, the wage earner's daughter, and Miguel S~, Jr.,
                  a citizen of the Philippines. Immediately after her birth, the natural parents gave
                  Mehlanie to the wage earner's wife, Catalina. Delivery and hospital expenses were
                  paid by the wage earner. Although the parties did not enter into a contemporaneous
                  written agreement, subsequent statements (contained in the claims file) made by the
                  wage earner and the natural parents indicate that Mehlanie was surrendered with the
                  mutual understanding that the wage earner and Catalina would "adopt" her and raise
                  her as their own child.
               
               Mehlanie remained in the Philippines in Catalina's custody for almost a year. In September
                  1975 they joined the wage earner in Guam, where he had been residing since 1971. Since
                  that time Mehlanie and the M~ have lived together on Guam. The M~ have stated that
                  they treat Mehlanie as their child and that she considers them to be her parents.
                  In 1980 legal adoption proceedings were begun by the wage earner (with the natural
                  parents' written consent), but due to lack of funds no final decree of adoption was
                  obtained.
               
               You have asked for our opinion as to whether or not Mehlanie has been equitably adopted
                  by the wage earner for purposes of entitlement to child's insurance benefits. Section,216(e)
                  (1) of the Social Security Act defines "child" to include legally adopted child of
                  the wage earner. Section 216 (h)(2)(A) of the Act provides that the determination
                  of the, existence of a child-parent relationship is to be based on the law of the
                  state in which the insured individual was domiciled at the time the application for
                  benefits was filed. Since the wage earner was domiciled in Guam [3] at the relevant time, the question to be resolved is whether or not Guam courts would
                  find that an equitable adoption has been effected.
               
               Section 1646 of the Guam Civil Code [4] provides:
               
               A contract is to be interpreted according to the law and usage of the place where
                  it is to be performed; or, if it does not indicate a place of performance, according
                  to the law and usage of the place where it is made.
               
               It appears that the natural parents and the M~ entered into an oral adoption agreement
                  in the Philippines. Therefore, substantive Guam law would apply only if the contracting
                  parties intended that the agreement was to be "performed" in Guam. If the parties
                  made no mention of the place of performance and did not otherwise assume or intend
                  a specific place of performance, then Philippine law — the law of the place where
                  the contract was made — must be applied.
               
               The statements of the wage earner and the natural parents do not indicate whether:
                  (1) it was contemplated that Mehlanie would remain in the Philippines; (2) it was
                  anticipated that she would reside with the McAuslens in Guam; or (3) if the place
                  of Mehlanie's residence (i.e., the place of performance for purposes of the adoption
                  agreement) was even considered by the parties. Any of these three possibilities is
                  plausible, based upon information currently in the claims file. The M~ evidently maintained
                  a home in the Philippines and, as late as May 1980, the wage earner described himself
                  (in an adoption petition drafted for presentation to a Philippine court) as only a
                  temporary resident of Guam. It may be that at the time Mehlanie was given to the M~,
                  the parties expected the wage earner to resume permanent residence in the Philippines
                  and to care for Mehlanie there. This hypothesis is reinforced by the fact that Mehlanie
                  and the wage earner's wife remained in the Philippines for nearly a year after her
                  birth. On the other hand, the wage earner has stated that he has lived in Guam since
                  1971 and Mehlanie has remained with him in Guam since she was brought there in 1975.
                  Thus, it could be assumed that the parties initially intended that the adoption agreement
                  would be performed in Guam. Finally, it is certainly conceivable that neither the
                  natural parents nor the wage earner and his wife even considered, much less agreed
                  upon, where Mehlanie was to live or to be adopted, so long as she remained in the
                  wage earner's custody.
               
               Because the pertinent Guam statute requires a determination as to where the contract
                  was to be performed (if any such location was "indicated" or agreed upon), further
                  development will be needed in this case. The parties to the adoption agreement — the
                  natural parents and the M~ — should be asked what understanding, if any, they had
                  as to the place of performance. If the topic never arose and the natural parents assumed
                  that Mehlanie would be adopted wherever the M~ lived, you should establish whether
                  the M~ anticipated securing the adoption decree in Guam or in the Philippines (or
                  if the issue of where Mehlanie would be adopted was considered at all).
               
               If the new information indicates that the parties intended the adoption agreement
                  to be carried out in Guam, the substantive law of that jurisdiction would apply on
                  the equitable adoption issue. Although no Guam statute or judicial opinion has specifically
                  addressed the question of equitable adoption, we are reasonably certain that Guam
                  courts would, as they have in other areas, follow California's lead and recognize
                  the existence of an equitable adoption under appropriate circumstances.
               
               See our opinions re Ngeaol A. O~, October 29, 1980, and Barbara J. E~ /Emily A~, August
                  31, 1979. The essential requirements for an equitable adoption under California law
                  are: (a) an express or implied contract of adoption, and (b) absolute surrender of
                  the child to the adopting parents. GC opinions re William M. N~, July 30, 1980; Thomas
                  K. S~, July 16, 1952; and John R. B~, November 29, 1982. The contract may be written,
                  oral, or implied from the conduct of the parties and the surrounding circumstances.
                  See GC opinion re Barbara J. E~, cited above, and cases cited therein.
               
               The contractual elements which Guam courts would likely require appear to have been
                  satisfied in this case. The natural parents and the M~ have stated that they entered
                  into an express oral contract whereby the natural parents relinquished Mehlanie absolutely
                  in return for the M~'s promise to adopt her. The circumstances surrounding the surrender
                  and the conduct of the parties during the ensuing years further substantiate the claim
                  that an unqualified adoption agreement was made at or about the time of Mehlanie's
                  birth. Therefore, were Guam courts free to apply their own law, it is our opinion
                  that a valid equitable adoption would be found. Pursuant to section 257 of the Guam
                  Probate Code, an adopted child succeeds to the estate of her adoptive parent to the
                  same extent as a natural child. Mehlanie, therefore, would qualify as the wage earner's
                  "child" under section 216(e) of the Act.
               
               If, however, the parties agreed that performance would take place in the Philippines,
                  or if an alternative place of performance was not specified or anticipated at the
                  time of agreement, Guam Civil Code section 1646 would require application of Philippine
                  law. Our preliminary research suggests that Philippine law does not recognize the
                  concept of equitable adoption. (See GC opinion re Feliciano N. N~, D-10063, July 7, 1964, which indicates that as of
                  1951 there was no provision for equitable adoption in the Philippines. We conferred
                  informally with the law librarian at the Library of Congress, who opined that the
                  relevant law likely remains the same today.) Accordingly, if newly developed facts
                  show that Philippine law governs interpretation of the agreement, you may wish to
                  resubmit the case to us for further definitive research on current Philippine law
                  respecting adoption of children.