Depending on the type of family relationship, foreign nationals can immigrate to the U.S. based on a petition filed by a family member. But there is a major difference in processing, depending on the type of relationship.
Immediate relatives: Under the immigration laws, an “immediate relative” is the parent, spouse, or child (unmarried and under the age of 21) of a U.S. citizen. Immediate relatives are at a distinct advantage over others as there is no visa wait list to immigrate. In other words, if the U.S. citizen files a petition for a foreign national parent, spouse or child, the foreign national will be eligible to receive a visa without being subject to a visa backlog (see below – “family preferences”). There are a few caveats, however. First, family immigration requires that the petitioner file an Affidavit of Support to prevent the sponsored family member from needing government assistance and to maintain the family member at a level of living above the poverty level. Second, cases involving marriage to a U.S. citizen are scrutinized for fraud. Only bona fide, good faith marriages will be approved. Third, if the marriage is less than two years old at the time of approval of the visa, the foreign national will be granted two-year conditional residence.
Family preferences: In addition to immediate relatives, the law provides immigrant visas for other family members. But Congress has placed a numerical limitation on visas for these other family members, so they are subject to a visa backlog. Note, the caveats listed above apply to family preferences too. Below are the other family members who can qualify for an immigrant visa and the approximate wait time for a visa. Bear in mind that a foreign national has no right to come to remain in the U.S. during the prolonged wait for a visa.
First preference — Adult, unmarried son or daughter of a U.S. citizen: 6-year backlog
Second preference (A) — Spouse or child of lawful permanent resident: 5-year backlog
Second preference (B) — Adult son or daughter (unmarried) of LPR: 8-year backlog
Third preference — Adult, married son or daughter of U.S. citizen: 9-year backlog
Fourth preference — Sibling of a U.S. citizen: 10- to 15-year backlog