Democratic Rep. Luis Gutierrez (Ill.) on Wednesday misidentified what a nuclear family is while criticizing President Donald Trump's immigration policy plan.

Gutierrez made the gaffe during an appearance on MSNBC with host Chris Hayes to discuss the immigration reform platform that Trump laid out in his State of the Union address on Tuesday.

One of the four pillars of Trump's immigration plan is to end chain migration, which allows green card holders or legal U.S. residents to sponsor relatives for immigration to the United States. The Trump administration wants to to limit sponsorships to spouses and minor children in order to prevent what some critics have called a "never-ending chain" of immigration to the country.

Many prominent Democrats, like Sen. Kirsten Gillibrand (D., N.Y.), have criticized the term as racist, saying it is intentionally used to "demonize" immigrant families.

Gutierrez, who Hayes introduced as an "immigration policy expert," gave his response to the president's remarks on preventing sponsorship for distant relatives.

"My wife's not a distant relative of mine," Gutierrez said. "Neither are my children, my parents, nor my sister, and those are the people that you can petition for. And they're not unlimited, right? I have a limited number of people in my life. They're my nuclear family."

Gutierrez appeared to confuse the term nuclear family, which the Merriam-Webster dictionary defines as a "family group that consists only of parents and children," with extended family, which includes an individual's other close relatives such as grandparents, aunts, and uncles.

Other dictionaries specify that a nuclear family only consists of parents and their children, or a couple and their dependent children, meaning Gutierrez's sister and parents would not be part of his nuclear family.

The mistake came after Gutierrez walked out of the State of the Union before Trump finished his speech. A spokesman for the congressman later clarified that the departure was not a protest, but rather because he had to get to an interview.

Gutierrez's comments also came one day after one of his Democratic colleagues, New York Rep. Joe Crowley, incorrectly said that a nuclear family includes one's "mothers and fathers, obviously, sons and daughters, brothers and sisters, and grandparents."

Gutierrez also told Hayes on Wednesday that Trump wants to create a "sense of fear" among Americans about immigrants coming to the U.S. in "uncontrollable numbers," adding that the president wants to stop "people of color" from entering the country.

"He [Trump] says it's about crime, right? But it's really not," Gutierrez said. "He says it's about a border and building a fence and building a wall, but it's not. It's about stopping legal immigration so that people like me, people like my mom that came to this country can't come here anymore."