If you are applying for U.S. lawful permanent residence (a green card) based on marriage to a U.S. citizen or lawful permanent resident, your foreign-born children may be eligible to obtain green cards along with you. This is true whether or not they are the biological children of your petitioning spouse.
The children won't automatically get green cards, however. They will have to not only meet some eligibility criteria, but go through the same or a very similar application process as you do. They will have to prove that they are not inadmissible and that they will be financially supported along with you.
If your children are unmarried and under age 21, they will (with very few exceptions, as you'll see below) be placed in the same category of applicant as you. The result will be that they get a visa or green card at the same time as you do.
If your children are married or over age 21, they might or might not be able to get a visa based on your U.S. spouse, and any visa they might get will take years longer than yours to obtain. Their eligibility will depend in part on whether your spouse is a U.S. citizen or a permanent resident, as discussed below.
Some of the visa possibilities for children of the immigrant depend on a biological parent-child relationship between the new U.S. citizen or permanent resident spouse and the children. Luckily, immigration law also recognizes certain nonbiological parent-child relationships, and includes the following as "children:"
If the petitioning spouse is a U.S. citizen and the unmarried children under 21 are his or her biological children or legal stepchildren (because you and your spouse married when they were under age 18), they qualify for green cards as the U.S. petitioner's immediate relatives.
Immediate relatives are given high priority under the immigration laws, with no annual limits—and therefore waiting periods—to slow their receipt of a green card. But there's one catch; they each need separate visa petitions filed on their behalf, using USCIS Form I-130.
Their I-130 petitions and then green cards should be approved at the same time as the immigrant spouse's (so long as they remain unmarried right up to the day they enter the U.S. with their immigrant visa, or if they're already in the U.S., receive approval of their adjustment of status application).
If any of your children marry before they receive a visa or green card, they will automatically drop into category 3 of the Visa Preference System, which is subject to long waiting periods.
What if one of your children turns 21 before receiving a visa or green card? Formerly, they would have dropped into category 1 of the Visa Preference System, but that was changed with the Child Status Protection Act of 2002 (CSPA). As long as the petitioner is a U.S. citizen and the child was under 21 when the visa petition was filed, the child will still be considered an immediate relative even after turning 21.
See How Spouses and Minor, Unmarried Children of Permanent Residents Can Change Visa Category for more on the above two issues.
If your spouse has a U.S. green card, your children who are unmarried and under age 21 are considered derivative beneficiaries. As a practical matter, this means that the children will not need a separate initial petition (Form I-130) filed for them in order to be included in your immigration process and enter the U.S. at the same time as you.
Unlike many other applicants, they also won't need to prove that the petitioning spouse is their parent or even stepparent, because they are riding on the immigrant's application.
Eventually, however, they will have to fill out forms of their own. They will share the immigrant's place on the visa/green card waiting list and most likely get a visa at the same time as the immigrant (provided they remain unmarried).
Children who have gotten married will not be able to immigrate to the United States at the same time as the others. They will have no visa options until the petitioning spouse becomes a U.S. citizen and files an I-130 petition for them in category 3 of the Visa Preference System (which has a very long waiting period). Of course, to do this, the spouse would have to prove that he or she is either the child's legal stepparent or the biological parent.
Another issue to be aware of is how turning 21 will affect your child's eligibility for a visa or green card. If your child turns 21 before his or her Priority Date has become current (that is, before visas are being allotted to people who applied at the same time as the primary immigrant), the child could, in theory, "age out," or drop into a lower Visa Preference category (2B), with a longer waiting period. Thanks to the Child Status Protection Act (CSPA) however, a child can actually turn 21 without turning 21 in the eyes of the law! That's because the law allows you to subtract from the child's age the amount of time that it took USCIS to approve your family's immigrant visa petition. But this won't save every child, so keep a close eye on the calendar.
Children who turn 21 after their Priority Date becomes current can keep their 2A status, but there's a catch. The child who has turned 21 must submit his or her green card application within a year of when the Priority Date became current.
If the permanent resident spouse becomes a U.S. citizen while you're still applying, the picture changes. See above to determine your children's visa eligibility and the application process.