Last December, when Andrew Emitt starting looking for college scholarships, he turned to his high school library, hoping to find Web sites that would guide him.
But the Tennessee 17-year-old is gay, and when he searched for organizations that might be friendly to LGBT (Lesbian, Gay, Bisexual and Transgender) students, he hit a firewall.
What he discovered is that 107 schools in Tennessee -- including his, Knoxville Central High School -- use software that can block Web sites catering to gay issues.
Emitt couldn't find any education sites, but he could find those that promoted "reparative therapy," which promises to change homosexuals to heterosexuals.
"I wasn't looking for anything sexual or inappropriate," said Emitt. "I was looking for information about scholarships for LGBT students, and I couldn't get to it because of this software. Our schools shouldn't be keeping students in the dark about LGBT organizations and resources."
"It wasn't anything for entertainment value. It wasn't looking for games or for chat rooms or for e-mails or for dating. It was scholarships," he said.
Now, Emitt and another high school student from Nashville have joined forces with the American Civil Liberties Union and threatened Metro Nashville and Knox County schools with a lawsuit, demanding they remove the filter to "educational and political" Web sites.
"If a gay student wanted to... get information about organizations that can help him, he wouldn't be able to," Metro High School student Eric Austin told ABC's affiliate in Nashville.
"It would be like an African American student not being able to get to the NAACP's Web site," said Austin, who is also seeking redress.
The ACLU claims these blocks violate the First Amendment and the federal Equal Access Law.
"Schools are a place for education and part of education is preparing students to be participants in the political process," said Christine Sun, senior counsel with the ACLU's LGBT Project.
"With so many people getting news from the Internet, how can we expect students to be part of the political process if we shield them from one side of the debate?"
Sun told ABCNews.com she had visited some of the "reparative therapy" Web sites that were permitted and "found some were sexually explicit."
The ACLU cites several medical associations, including the American Academy of Pediatrics, which deem the practice as "dangerous and harmful" to young people.
The ACLU sent an April 15 letter to members of the Tennessee Schools Cooperative: Dr. James McIntyre, Knox County Schools superintendent; Dr. Jessie Register, Metro Nashville Public Schools director and Dr. Lyle C. Ailshie, director of the Greenville City Schools, warning them of the impending lawsuit.
The cooperative -- which represents all but 30 schools in Tennessee -- was given until April 29 to respond and was asked to lift the blocks by next fall or face a lawsuit.
Russ Oaks, spokesman for Knox County Schools, told ABCNews.com, "We've received the information from the ACLU and we've referred it to the Knox County Law Director's office for review."