Comment by richard___

On paper, H1B is a temporary worker program that requires non-immigrant intent. In practice, there is a legal fiction called “dual intent” that allows H1Bs to apply for a green card without violating the requirement of non-immigrant intent. Once a permanent resident, they can sponsor spouses and adult children for permanent residency. Once a citizen, they can sponsor parents and siblings.

The U.S. gave my dad an H1 visa, which resulted in 8 other Bangladeshis moving to the U.S. If my mom wasn’t antisocial, she could’ve sponsored her dozen siblings, who could’ve then sponsored their children. That’s how you end up with ethnic enclaves like Little Bangladesh.

In the case of the H1-B visa holder's children, the Birthright Citizenship Clause of the 14th amendment.

Basic US immigration law: once a permanent resident or a citizen, a former H1B holder can bring his relatives, like any US citizen