A pair of 16-month-old twin boys have been given different citizenship statuses by the US government.
Aiden and Ethan Dvash-Banks were born within four minutes of each other, but only Aidan has been granted citizenship for their country of birth.
They legally share the same fathers, a legally married gay couple, and come from the same mother.
But, because Ethan shares his DNA with his Israeli-born father, he has been denied the US citizenship and is undocumented.
Ethan was granted a temporary tourist visa, but this has now expired.
Their fathers, Andrew and Elad Dvash-Banks, are now challenging a policy they say discriminates against LGBT parents by refusing birthright citizenship based on blood relationships.
"The message is that you're not fully equal. Your family is less than other families," Andrew Dvash-Banks told the Guardian.
"My son has been wronged here by the government. We're fighting this to protect our son and our family."
The couple have now taken the fight to court, saying that if they were a heterosexual couple, Ethan would have been granted citizenship automatically.
They're filing in parallel to a lawsuit from a lesbian couple who face a similar problem - one of their sons has been given US citizenship, while the other was declined due to his Italian-born mother carrying him.
The US state department would not comment on the case to the Guardian.
The Dvash-Banks family say they're hopeful they will eventually win the suit and ensure no other families will have to fight the government for their child's birthright citizenship.