Citizenship of the U.S., like citizenship of Ireland, can be passed on from a parent to a child who is born in a foreign country under certain circumstances. For many years Irish people were not aware of this section of U.S. law. At best, people born in Ireland to U.S. citizen parents thought they might be eligible for a green card under the family preference category, or if they were eligible for U.S. citizenship that it was a long and arduous application process. However, there are often options available to children born abroad to at least one U.S. citizen parent which may grant U.S. citizenship at birth. The rules for determining whether U.S. citizenship is transferred from a parent to a child at birth are complicated and for the most part depend on the date of birth of the child. This is because the section of U.S. law that defines this was changed many times over the past hundred years or so. The particular version of this law which is in existence at the time of the child's birth will determine if U.S. citizenship was transferred automatically. In general, a child born abroad to two U.S. citizen parents acquires U.S. citizenship automatically at birth as long as one of the parents resided in the United States for any length of time prior to the birth of the child, according to the Immigration and Nationality Act's Section 301(c). Section 301(g) of the INA lays out the conditions under which a child, born abroad to one U.S citizen parent and one non-U.S. citizen parent, acquires U.S. citizenship automatically at birth. As I've mentioned previously, this section has been changed several times by various acts of Congress. Each time the Congress changes Section 301(h), the new conditions apply only to people born on or after that date. For children born abroad on or after November 14, 1986 to one U.S. parent and one non-U.S. parent, the following formula will apply - if the U.S. parent had lived in the U.S. for five years, two of which are after the age of 14 prior to the birth of the child abroad, then the child automatically acquires U.S. citizenship at birth and is entitled to obtain a U.S. passport, according to Section 301(g) of the INA. If both parents are U.S. citizens at the time of the child's birth, and if either parent had resided in the U.S. at any time in their lives prior to the child's birth then the child also acquires U.S. citizenship automatically at birth, according to Section 301(c) of the INA. For children born abroad before November 14, 1986, the formula is slightly different. The previous version of Section 301 that conferred U.S. citizenship on a child born abroad to one U.S. parent and one non-U.S. citizen parent, required that the U.S. citizen parent had lived in the United States for 10 years, two of which were after the age of 14. This version of Section 301(g) covers children born abroad between December 24, 1952 and November 14, 1986. The only difference is that the newer version of INA Section 301(g) requires the U.S. citizen parent to have lived in the United States for a shorter time, five years instead of 10 years, prior to the birth of the child. For children born abroad to one U.S. citizen parent between May 24, 1934 and December 24, 1952 the conditions for acquiring U.S. citizenship automatically are more complicated, partly because of the involvement of the U.S. in the Second World War. . Prior to May 24, 1934 the formula is again very simple and only requires that the U.S. citizen resided at any time prior to the child's birth abroad. There is no requirement that the child must have "claimed" their U.S. citizenship before the age of 18 or 21. Under the law I have outlined above, U.S citizenship is acquired automatically at birth and cannot be lost. James A. O'Malley is the senior attorney in the law firm of O'Malley and Associates in New York City. The firm practices all areas of U.S. citizenship, nationality and visa law. O'Malley is a native of Limerick City and a graduate of University College Galway.