DALLAS — Mirian Villalobos had plenty going for her. The 25-year-old had a dimpled son, a handsome husband, a new house, and a happy suspicion she was pregnant again.

Then, it unraveled.

On a balmy Sept. 6 in Wilmer, Texas, outside Dallas, she was pulled over by the police as she rode on the back of a motorcycle driven by her husband, 30-year-old Juan Espinoza. She was stopped for not wearing helmet, but a routine check of her record found an arrest warrant. She'd been ordered to report for deportation in 2002.

Caught in the middle: an infant named Kevin Isaac, born a U.S. citizen with a father in the U.S. legally and a mother in the U.S. illegally. Villalobos was deported.

Unable to bear the separation from her son, now 9 months old, she returned to the U.S. in October and was detained in Arizona.

This month, she was deported again to Honduras, without seeing her young son and now six months pregnant, her husband says.

Her story is one echoing through many families with mixed immigration status, as a crackdown on illegal immigrants cleaves communities. There are 3.1 million children in the U.S. with one or two parents without legal immigration status in 2005, according to the Pew Hispanic Center.

Before the first deportation, an attorney for Villalobos had asked that she be allowed to stay in the U.S. on humanitarian grounds. The request was denied by the Dallas regional office of U.S. Immigration and Customs Enforcement, an agency within the Homeland Security Department.

A U.S. citizen child confers no benefits to parents, or a parent who is in the U.S. illegally, except in very rare cases, said Carl Rusnok, a spokesman for ICE. Parents are ultimately responsible, he said.

"Any parent should take into consideration how their decisions to defy our nation's laws will affect their families," Rusnok said.

On Oct. 4, Villalobos was deported and flown to Tegucigalpa, the capital of her native Honduras.

As her husband tells it, Villalobos was left at the airport in a city she didn't know in a Central American country she left as a teenager. Immigration officials gave her a good-bye of "Que se vaya bien," may it go well for you.

Honduras, with a population of 7.4 million, is one of the poorest countries in the Western Hemisphere with a per-capita income of $1,170 per year. In 2006, 20 percent of the economy's gross domestic product came from remittances, the money sent home to Honduras by its emigrants, according to the World Bank.

By comparison, remittances made up only about 3 percent of the GDP of Mexico, a nation of 104 million with a far stronger economy.

The scope of the crackdown against illegal immigrants in mixed-status families is raising new questions, and many are beginning to question the treatment of the most vulnerable of immigrants: women, pregnant women and their children.

So many U.S. citizen children have been affected by deportations and work site raids that the Urban Institute, a research center in Washington, D.C., is conducting a study to determine the different types of treatment in family courts and criminal courts vs. immigration courts. It was brought on in part by immigration raids a year ago at meatpacking plants in Cactus, Texas, and other locations owned by Swift & Co.

Joseph Hammell, a Minneapolis attorney assisting the Urban Institute, said there were few protections for citizen children caught in an immigration deportation involving parents in the U.S. unlawfully. There are no court-appointed attorneys, for example, he said.

"There is no one really looking out for the child," Hammell says. "This is one thing that has riled people.

"Our immigration laws seem to be inconsistent with our broader societal issues in terms of protecting children, and that inconsistency needs to be addressed, even if that means moderate reform in the statutes to protect the best interests of children."

Villalobos' attorney up until the first deportation, Rudy Castillo, acknowledged that Villalobos' case was a difficult one. "There are more and more cases where there are no remedies or little remedy," Castillo said. "It depends on their previous run-ins with immigration. Those are all red flags for new relief."