The Attorney General appeals the district court’s grant of summary judgment declaring Mary Ruth Burgess a citizen of the United States under the Immigration and Nationality Act §§ 301(g) and 309(a), 8 U.S.C. §§ 1401 (g) and 1409(a)(1983). We affirm.

FACTS

Mary Ruth Burgess (“Mary”) was born September 28, 1962 in Tijuana, Mexico. Her mother, Josefine Carrillo, is a native of Colima, Mexico. Her father, Don L. Burgess (“Don”), was a native of Pikesville, Tennessee, USA. Mary’s parents never legally married, but lived together in Tijuana, Mexico for ten years until Don’s death on June 1, 1963 in Tijuana. Mary’s birth certificate was registered by her mother on June 7, 1963 in Tijuana, six days after Don’s death.

Mary entered the United States in 1979. She married in Yakima, Washington on September 27,1980. On April 15,1983, she obtained a declaration of paternity from the Superior Court of Washington for Yakima County establishing Don as her natural and legal father pursuant to WasLRev. Code Ann. § 26.26 (West 1986).

Mary submitted her claim to citizenship to the Immigration and Naturalization Service which was denied by the District Director on October 25, 1983. This decision was upheld within the Agency’s appeal process.

On April 27,1984, Mary filed a complaint for declaratory judgment of citizenship in the district court. The district court dismissed her complaint with prejudice on September 20, 1984 because her marriage prevented her from meeting the statutory definition of “child” under 8 U.S.C. § 1101 (b)(1)(C). The district court determined, however, that Mary’s residence in Washington allowed her legitimation under the laws of Washington for the purpose of derivative citizenship except that she was not “unmarried.”

On November 1, 1984, Mary obtained an annulment of her marriage from the Superior Court of Washington for Yakima County. The annulment was granted on the ground that she married while still a minor without the consent of her parent or guardian. Following her annulment, the district court on April 8, 1985 granted her motion pursuant to Fed.R.Civ.P. 60(b) to vacate its prior order of September 20, 1984, and then granted her summary judgment motion declaring her a statutory citizen of the United States. The Attorney General appeals. We affirm.

STANDARD OF REVIEW

The granting of summary judgment is reviewable de novo. Haluapo v. Akashi Kaiun, KK, 748 F.2d 1363, 1364 (9th Cir. 1984). Summary judgment is proper when there is no genuine issue as to any material fact and the moving party is entitled to *340 judgment as a matter of law. Fed.R.Civ.P. 56.

DISCUSSION

This case presents the question whether a daughter born in Mexico, of a Mexican citizen and a United States citizen who never legally married, can satisfy the requirements for statutory citizenship under the Immigration and Nationality Act §§ 301(g) and 309(a), 8 U.S.C. §§ 1401 (g) and 1409(a) (1983).

Under 8 U.S.C. § 1401 (g), a person shall be a national and citizen of the United States at birth who is:

The district court found, and it is undisputed, that Don was physically present in the United States for the period required by 8 U.S.C. § 1401 (g) so that a child born to him out of wedlock may acquire United States citizenship. Section 1401(g) is applicable under section 1409(a) to children born out of wedlock “as of the date of birth ... if the paternity of such child is established while such child is under the age of twenty-one years by legitimation.” 8 U.S.C. § 1409 (a). Thus, to obtain citizenship Mary must prove legitimation took place while she was under twenty-one years of age.

Legitimacy is a legal concept, and the law determines whether and under what circumstances a child it has denominated illegitimate may become legitimate. Lau v. Kiley, 563 F.2d 543, 548 (2d Cir. 1977). The Immigration and Nationality Act provides that a child who is unmarried and under twenty-one years of age can be legitimated

8 U.S.C. § 1101 (b)(1)(C) (1983) (emphasis added). Under the statute a child may be legitimated under any of four potential sources of law that recognizes legitimating acts of the parent, and we have held that a state can recognize legitimating acts occurring before either the father or child have any contact with that state. Kaliski v. Disk Dir. of Immigration and Nat. Serv., 620 F.2d 214, 216 (9th Cir.1980).

In the case at bar, the Attorney General contests the district court holding of Mary’s legitimation under Washington law, and contends that the government has long required that legitimation occur under the law of the father’s domicile, which is Mexico or California in the instant case. He cites opinions of the Attorney General, Board of Immigration Appeals, and the federal district court in Rios v. Civiletti, 571 F.Supp. 218 (D.Puerto Rico 1983), in support of his position. This interpretation of 8 U.S.C. § 1409 (a) by the Attorney General contradicts the plain language of the statute, 8 U.S.C. § 1101 (b)(1)(C), which provides that a child, for the purposes of 8 U.S.C. § 1409 (a), can be legitimated under “the law of the child’s residence or domicile, or under the law of the father’s residence or domicile.”

Here, the law of Washington state, where Mary resides, is the law of the “child’s residence or domicile”, § 1101(b)(1)(C), and it provides that a man is presumed to be the natural father of a child if “[wjhile the child is under the age of majority, he receives the child into his home and openly holds out the child as his child.” Wash.Rev.Code Ann. § 26.26.040 (West 1986). 1 The operative facts here are *341 that Don, Mary’s father, lived with Josefine Carrillo, Mary’s mother, for ten years prior to his death, and during those years Mary was born to the union. Don continued to live with Josefine after Mary’s birth until his death and inferentially held Mary out as his natural daughter. These are the facts explicitly found by the Superior Court of Washington for Yakima County on April 15, 1983 and implicitly- by the district court on September 20, 1984 and April 8, 1985. Don legitimated Mary by receiving her into his home and openly holding her out as his child from her birth until his death.

The result here accords with our decision in Kaliski (California law applied to legitimating acts that occured in Yugoslavia); the Board of Immigration Appeals’ decision In re Fulgencio, 17 I & N Dec. 471 (1980) (California law applied to legitimating acts that occurred in the Philippines) and the district court’s decision in Rios v. Civiletti (Puerto Rican law applied to legitimating acts that took place in Mexico.) In each case the law of the forum state was applied to acts of a father acknowledging and recognizing the child as his own, and these acts occurred prior to either the child or the father having contact with the forum state.

The Attorney General’s final contention is that the district court improperly accorded deference to the Washington Superior Court paternity decree which it asserts was based on the birth certificate filed six days after Don’s death by Mary’s mother in Mexico. We agree that the filing of the birth certificate by the mother after the death of the father cannot qualify as a legitimating act by the father. We disagree, however, that the Washington decree is so based because it nowhere recites the fact of the registration of the birth certificate. Rather it found that the child was born to the father and mother who were “never married, but lived together in Tijuana, Mexico, for ten (10) years until Don Burgess’ death in 1963 in Tijuana.”

The district court determined that these facts were sufficient to support the conclusion that Don, the father, legitimated Mary, the daughter, for purposes of 8 U.S.C. § 1101 (b)(1)(C). We should point out that the United States was not bound by the decree of the Washington Superior Court and was not collaterally estopped to challenge and attack the validity of that decree. The Government, however, offered no evidence to cast doubt upon that decree. Neither was there any disagreement between the parties as to the material facts. The district court, in an independent, adversarial proceeding with the Attorney General and the Immigration Service in opposition, properly concluded that legitimation took place when the father received the child into his home and held her out as his child, at a time before the child reached the age of eighteen years, and while the child was in the legal custody of the legitimating parent. Mary is entitled to derivative citizenship under 8 U.S.C. §§ 1401 (g) and 1409(a). The grant of summary judgment by the district court declaring Mary Ruth Burgess a citizen of the United States is

AFFIRMED.

. Even were we to apply California law as the law of the father’s domicile to legitimating acts *341 which occurred in Mexico, the Attorney General’s appeal would fail because California and Washington have both adopted the Uniform Parentage Act. This same statutory language can be found in California Civil Code Ann. § 7004(a)(4) (West Supp.1986).