Students running a campaign in support of the federal Employment Non-Discrimination Act were shocked today to discover that someone had defaced the signs with obscene messages.

The signs, which were made by the Fierce Advocates — a new undergraduate organization dedicated to political action for full equality of LGBTQ people — listed examples of employment discrimination toward LGBTQ people, and encouraged people to visit the Web site for the “Pass ENDA Now” campaign. The signs were placed on Cross Campus Sunday.

But at 11 a.m. Tuesday, two members of Fierce Advocates saw that the signs had been turned over and mocking messages were written on the back. The sign that originally read “In 29 States You can be fired, just for being lesbian” was changed to “You can get any guy you want, just for being lesbian.” Similar messages appeared on the other signs, including one sign about transgender discrimination that was defaced with a message about sex reassignment surgeries in the Soviet Union.

“I honestly was not very surprised,” said Amalia Skilton ’13, the director of Fierce Advocates. She said she faced similar negative attitudes toward LGBT activism in high school.

But Skilton maintained that she was taken aback by the audacity of the defacement.

“I do think this is a lack of respect for freedom of expression at Yale,” she said.

Skilton sent a letter Tuesday to Yale College Dean Mary Miller about the vandalism, and said she hopes Yale College administrators will reiterate to students the right to freedom of expression on campus.