US President Donald Trump's son-in-law and senior adviser voted in November's US presidential election as a woman, the media reported on Thursday.
Registration records show that when Kushner, who is married to first daughter Ivanka Trump, registered to vote in 2009, he apparently checked a box classifying his gender as a female, The Hill reported.
Democratic opposition research group American Bridge first spotted the error, which the Wired then reported.
"Kushner can't even fill out the most basic paperwork without screwing it up, so it's a mystery why anyone thinks he's somehow going to bring peace to the Middle East," Brad Bainum, a spokesperson for the group, told Wired about the mistake.
"Would anyone but the president's son-in-law still have a West Wing job after repeated disclosure errors and a botched security clearance form?"
Kushner, who has a vast portfolio of issues at the White House, has had to amend his federal security clearance forms multiple times to include meetings with foreign contacts.
He told congressional investigators that the mistakes have been due to a "miscommunication" with his assistant.
Prior to 2009, his New Jersey voter registration noted his gender as "unknown".