The lawsuit was originally filed in May by the Texas Civil Rights Project and Texas Rio Grande Legal Aid. It was amended Tuesday so that the civil rights groups could represent "a large number of plaintiffs."
The lawsuit originally included six families as plaintiffs. The number as of Tuesday was 17, and the civil rights groups say they're getting ready to represent many more families.
At issue is the validity of a form of ID that undocumented immigrants, mainly Mexicans and Central Americans, use to obtain a birth certificate for their children born in the United States.
Jim Harrington, a civil rights attorney, says Texas state authorities used to accept the matricula consular, an identification card issued by the consulates of Mexico and other countries.
But Harrington, the director of the Texas Civil Rights Project, says the Texas Department of State Health Services, which issues birth certificates, recently reversed its policy and stopped accepting consular IDs.
"It had never been an issue before. It was relatively easy for families of these U.S.-born children to get a birth certificate," he said in a phone interview with CNN.
Not having a birth certificate leaves a child born in the United States to undocumented parents in legal limbo. The child is unable to get medical services or register for school, for example. Technically, it also makes the child deportable.
Harrington said he considers the action of the state of Texas "a violation of the 14th Amendment of the U.S. Constitution and its Equal Protection Clause." The amendment, ratified in 1868, says in part that "All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside."
But Chris Van Deusen, a spokesman with the Texas Department of State Health Services, said the policy has nothing to do with discrimination.
"DSHS provides certified birth certificates without regard to the requestor's immigration status and has never accepted the matricula consular as adequate identification," he said.
Van Deusen also said that the problem for the state of Texas is that the documents used to obtain consular IDs "are not verified by the issuing consulate." He added that other states and federal agencies reject consular IDs for the same reason.
The state of Texas provided CNN with a list of valid documents of identification. The list includes foreign passports accompanied by a visa issued by the U.S. State Department, a Mexican voter registration card or even a foreign identification with an identifiable photo of the applicant.
Harrington, the civil rights attorney, insists that while the policy's stated purpose of making the process more secure sounds fair, the effects of this policy and its application are devastating to children born in the United States.
"Frankly, I think this is part of the state's anti-immigrant stance our political leaders have. They talk about making the process more secure, but that's nonsense. They're just building barriers so that people don't register their children," he said.