American Children Struggle to Adjust in Mexico Shaul Schwarz for The New York Times Jeffrey Isidoro, from Texas, now lives in Mexico with his family. IZÚCAR DE MATAMOROS, Mexico - Jeffrey Isidoro sat near the door of his fifth-grade classroom here in central Mexico, staring outside through designer glasses that, like his Nike sneakers and Nike backpack, signaled a life lived almost entirely in the United States. His parents are at home in Mexico. Jeffrey is lost. When his teacher asked in Spanish how dolphins communicate, a boy next to him reached over to underline the right answer. When it was Jeffrey's turn to read, his classmates laughed and shouted "en inglés, en inglés" - causing Jeffrey to blush. "Houston is home," Jeffrey said during recess, in English. The houses and stuff here, it's all a little strange. I feel, like, uncomfortable. Never before has Mexico seen so many American Jeffreys, Jennifers and Aidens in its classrooms. The wave of deportations in the past few years, along with tougher state laws and persistent unemployment, have all created a mass exodus of Mexican parents who are leaving with their American sons and daughters. In all, 1.4 million Mexicans - including about 300,000 children born in the United States - moved to Mexico between 2005 and 2010, according to Mexican census figures. That is roughly double the rate of southbound migration from 1995 to 2000, and new government data published this month suggest that the flow is not diminishing. The result is an entire generation of children who blur the line between Mexican and American. "It's really a new phenomenon," said Víctor Zúñiga, a sociologist at the University of Monterrey, in Nuevo León State, which borders Texas. It's the first time in the relationship between Mexico and the United States that we have a generation of young people sharing both societies during the early years of their lives. Critics of immigration have mostly welcomed the mass departure, but demographers and educators worry that far too many American children are being sent to schools in Mexico that are not equipped to integrate them. And because research shows that most of these children plan to return to the United States, some argue that what is Mexico's challenge today will be an American problem tomorrow, with a new class of emerging immigrants: young adults with limited skills, troubled childhoods and the full rights of American citizenship. "These kinds of changes are really traumatic for kids," said Marta Tienda, a sociologist at Princeton who was born in Texas to Mexican migrant laborers. It's going to stick with them. Jeffrey's situation is increasingly common. His father, Tomás Isidoro, 39, a carpenter, was one of the 46,486 immigrants deported in the first half of 2011 who said they had American children, according to a report by Immigration and Customs Enforcement to Congress. That is eight times the half-year average for such removals from 1998 to 2007. Mr. Isidoro, wearing a Dallas Cowboys hat in his parents" kitchen, said he was still angry that his 25 years of work in the United States meant nothing; that being caught with a broken taillight on his vehicle and without immigration papers meant more than having two American sons - Jeffrey, 10, and his brother, Tommy Jefferson, 2, who was named after the family's favorite president. As for President Obama, Mr. Isidoro uttered an expletive. "There are all these drug addicts, drug dealers, people who do nothing in the United States, and you're going to kick people like me out," he said. White House officials have said that under a new policy focused on criminals, fewer parents of American children are being deported for minor offenses. On Friday, the Obama administration also announced that hundreds of thousands of illegal immigrants who came to United States as children would be allowed to stay without fear of deportation. The policy, however, does not grant legal status, and because nearly half of the country's 10.2 million illegal immigrant adults have children, experts say that inevitably more families will be divided - especially if deportations over all hold steady around 400,000 a year. But for Jeffrey, the impact of his father's removal in June last year was immediate. His grades dipped. His mother, Leivi Rodríguez, 32, worried that he had become more distant, from both his friends and his studies. Almost every day, Jeffrey told her he wanted to see his father. Shaul Schwarz contributed reporting.