(B)  Acquired Citizenship.  The person may have acquired citizenship at birth from his or her parents if one or both natural parents was a United States citizen at the time s/he was born, even if s/he was born outside the United States.[10]

[10] See INA § § 301(c), (d), (e) & (g), 301a, 303, 8 U.S.C. § § 1401(c), (d), (e), & (g), 1401a, 1403; and INA § 309, 8 U.S.C. § 1409 (child born out of wedlock).  The formulae for determining the citizenship of the child of one or more parents, who were U.S. citizens when the child was born, are described in I. Kurzban, Kurzban’s Immigration Law Sourcebook 775 (2004); Swanson, Challenging Alienage – Is Your Client a U.S. Citizen, in ILRC Appendix 9-A (2004).  Other sources with more information on citizenship include Naturalization: A Guide for Community Advocates (ILRC, 1663 Mission St., Suite 603, San Francisco CA 94103); D. Levy, U.S. Citizenship and Naturalization Handbook (West Group 2000); B. Hing, Handling Immigration Cases (Federal Publications); National Lawyers Guild, Immigration Law and Defense (West Publishing 2002); the multi-volume Mailman, et al., Immigration Law and Procedure (Matthew Bender 2002); Mautino, Acquisition of United States Citizenship, Bender’s Immigration Bulletin, Vol. 6, No. 1 (Jan. 2001).  It is also possible that the defendant’s grandparents were U.S. citizens, thus transmitting U.S. citizenship to the defendant’s parents, who in turn transmitted it to the child.

Second Circuit

CITIZENSHIP - ACQUIRED CITIZENSHIP - BIOLOGICAL PARENTAGE IS NECESSARY TO A CLAIM TO UNITED STATES CITIZENSHIP UNDER FORMER INA 301(a)(3)
Colaianni v. INS, 490 F.3d 185 (2d Cir. Jun. 15, 2007) (per curiam) (petition for review denied on basis that noncitizen's claim to be United States citizen, advanced as a defense in removal proceedings, was invalid, since biological parentage is necessary for a person to claim citizenship under former INA 301(a)(3) because of the plain language of the statute, which refers to persons "born ... of parents both of whom are citizens of the United States" and pertains only to the acquisition of citizenship "at birth."), citing Marquez-Marquez v. Gonzales, 455 F.3d 548, 556-57 (5th Cir.2006) (rejecting the same argument based upon a plain reading of the statute).

Lower Courts of Second Circuit

CITIZENSHIP - UNCONSTITUTIONAL TO CONVICT OF ILLEGAL REENTRY
Perez v. United States, ___ F.Supp. ___, ___ (D.N.Y. 2006) ("[B]ecause Petitioner has established that he is a United States citizen, it is a constitutional violation to convict him for reentering the United States. As a result, the Court finds that Petitioners conviction and, in turn, his sentence should be vacated pursuant to 28 U.S.C. 2255.")

Fifth Circuit

CITIZENSHIP - BIRTH IN UNITED STATES
Lopez v. Holder, ___ F.3d ___, 2009 WL 682991 (5th Cir. Mar. 17, 2009) (without consent of petitioners, magistrate judge did not have jurisdiction to try citizenship case based on birth).

Other

ILLEGAL REMOVAL OF UNITED STATES CITIZENS
Occasionally, persons are placed in removal proceedings, and even removed, even though they are United States citizens. E.g., Diaz v. Reno, 40 F.Supp. 2d 984 (N.D. Ill.1999) (U.S. citizen who had been ordered summarily excluded from the United States mounts several claims related to summary exclusion after returning to the United States); Fierro v. INS, 66 F. Supp. 2d 229 (D. Mass. 1999) (court enjoins removal of individual pend-ing resolution of claim to United States citizenship).

CITIZENSHIP - FOUNDLINGS
INA 301(f) allows "a person of unknown parentage found in the United States while under the age of five years" to be considered a citizen of the United States unless the person is "shown, prior to his attaining the age of twenty-one years, not to have been born in the United States."

CITIZENSHIP - PROOF OF - CENSUS INFORMATION
United States Citizenship may be sometimes proven by showing a child appeared on a U.S. census in the United States shortly after birth. Contact US Census Bureau. Thanks to Mary Lee Eldridge