A gay binational couple filed a lawsuit Monday against the U.S. State Department on behalf of their 16-month-old who, unlike his twin brother, has been denied U.S. citizenship.

Ethan and Aiden Dvash-Banks are toddler twins of Elad Dvash-Banks, an Israeli national, and Andrew Dvash-Banks, an American citizen. Ethan, the biological son of Elad, does not have a U.S. citizenship.

Ethan Dvash-Banks became a plaintiff in a federal lawsuit against the State Department that seeks the same rights his brother, Aiden, has as an American citizen.

An LGBTQ immigrant rights lawyer filed the suit on behalf of the family, arguing that the U.S. is discriminating against the couple by denying their child citizenship at birth.

The twins were born in Canada in 2016 but the lawsuit alleges that they should be eligible for U.S. citizenship, since their surrogate mother is a U.S. citizen.

The State Department's website says there must be a biological connection to a U.S. citizen to become a citizen at birth.

Andrew Dvash-Banks was studying in Israel when he met his future husband, Elad, an Israeli citizen. Because they couldn't marry at the time in the U.S. or in Israel, they moved to Canada, and wed in 2010.

Ethan and Aiden are legally the exclusive parents of Andrew and Elad, who shared a surrogate, The Guardian reported.

The couple brought their infants to the American consulate in Toronto to apply for citizenship. The consular official told them a DNA test was required to show who the biological father was of each boy and without those tests neither son would get citizenship.

After submitting the DNA test results that proved who fathered each boy, the couple received Aiden's passport and a letter notifying Andrew that Ethan's application had been denied.

“The message is that you’re not fully equal. Your family is less than other families,” said Andrew Dvash-Banks. “My son has been wronged here by the government.”

The family has since moved to Los Angeles to be closer to Andrew Dvash-Banks' family. Ethan’s tourist visa expired last month, and he is currently applying for a green card, Andrew Dvash-Banks said.

The Associated Press contributed to this report.