A Colorado resident denied a passport for refusing to check either male or female on the application form has sued the federal government to push for a third option.

Lambda Legal announced the lawsuit Monday, saying it wants the United States to join countries like Australia, New Zealand and Nepal that allow people to have their sex marked as "x'' or "other" rather than male or female.

The organization filed the lawsuit against Secretary of State John Kerry on behalf of Dana Zzyym in Denver federal court. It claims that the current practice of requiring people to choose between male and female is discriminatory and asks people like Zzyym, who was born with ambiguous sex characteristics, to lie.

The State Department said it wouldn't comment on pending litigation.