From the BBC:

They were brought to the US at a young age by the parents, first generation immigrants who often still have close ties to their home countries. Younger brothers and sisters were born in America, second generation immigrants who enjoy the status of US citizens. Not Generation 1.5. Despite having lived most of their lives in the US and speaking fluent English, many cannot legally work, vote or drive in most US states. They are subject to arrest and deportation just like any other undocumented migrant. "They fear being deported but many of them don't know (anything) other than English, so they have no idea what awaits (them) in their countries of origin, said Ruben Rumbaut of the University of California in Irvine, who coined the Generation 1.5 term. There are no official figures of how many undocumented children live in the US, but the Pew Hispanic Center estimates that 7 percent of all Hispanic children are unauthorised immigrants.

For the full story, please visit http://news.bbc.co.uk/2/hi/world/us_and_canada/10209099.stm.