Leaders of the Graduate Employees and Students Organization on Wednesday delivered a letter to Yale President Richard Levin calling for recognition as a union, and said afterwards that many graduate students have been receptive to the possibility of a teaching assistant strike this semester.

About a dozen GESO members delivered the petition, along with a report the group released this week about the low number of female and minority tenured professors in the Ivy League. In the last few weeks, discussions among graduate students about a possible TA strike this semester have heated up, although GESO organizers said they have not yet decided whether to call a strike vote.

Although GESO organizers are considering a range of strike options, GESO Chair Mary Reynolds GRD ’07 said, they have not considered staging a grade strike, during which TAs would refuse to release students’ final grades. But she said that conversations among fellow graduate students and GESO members regarding a potential strike have been going “really well.”

The threat of a strike has not phased Yale officials, who will refuse to recognize GESO as a union, University spokesman Tom Conroy said.

“The University has never met with GESO and will not meet with [the group],” Conroy said. “The University believes that all graduate students who have teaching responsibilities at any given time need to fulfill those responsibilities, and that is the expectation of the administration, and if for any reason that doesn’t occur, the University will address it.”

The administration has had a long-standing position against graduate student unionization and is adhering to a National Labor Relations Board ruling last summer that refused to grant employee status to teaching assistants at private universities.

GESO organizer Shana Redmond GRD ’08 said she thinks many graduate students are frustrated that the administration has not responded directly to GESO complaints regarding faculty diversity. In addition, she said, GESO members are angry at Levin for not condemning Harvard President Lawrence Summers for his remarks regarding a paucity of women in the sciences.

“Throughout the year, slowly but surely, we have been accumulating these responses from the University that have been dismissive,” Redmond said. “There’s a sense that there’s something significantly wrong with the way things are right now, and there needs to be some kind of intervention to actually fix it.”

But Rachel Mae Anderson GRD ’05, a member of the anti-unionization group At What Cost, said she does not think a strike would be supported by graduate students.

“I feel like we haven’t heard any news about, and I have heard of no grad students that are willing to strike,” Smith said. “[GESO has] lost the respect and support of so many graduate students who actually care about those issues. There are other groups that are actually tackling these issues anyway — they’re the noisiest group on the block, but they’re not the most effective.”

Smith added that she is concerned about the impact a strike would have on undergraduates.

Biophysics and biochemistry professor William Summers, who teaches the popular undergraduate lecture course “Biology of Gender and Sexuality,” said that he is uncertain about the effect a TA strike would have on his class. Summers’ class of about 550 students has 14 teaching assistants, but most of them are scattered throughout the professional schools; few are enrolled in the Graduate School, Summers said.

“To what extent these people would or would not [strike], I have no notion of the level of participation,” Summers said. “If my teaching assistants were to not work with me for the rest of the semester, we’d do our best to work around it.”

When about 10 percent of TAs at Columbia went on strike last spring during final exams period, faculty teaching lecture courses with discussion sections run by TAs on strike took responsibility for grading their students’ work. Members of the existing teaching staff were recruited to help grade the work of students affected by the strike. Some non-graduating students in courses affected by the strike experienced delays in receiving their grades, and the university guaranteed a grading process that was as equitable as possible.

Columbia’s graduate TAs who went on strike were not penalized, and they continued to receive their stipends, tuition remission and other benefits included in their financial aid package. Yale Graduate School Dean Jon Butler said last month that graduate students on strike at Yale could expect the same, in accordance with University policy.

In April 1995, some graduate TAs at Yale went on a grade strike for a week, during which they refused to teach sections or grade papers or exams. The timing was particularly difficult for undergraduates, as the strike occurred just before reading period, at a time when many papers were due. But the 1995 GESO strike did not impact the administration’s stance.

GESO has gone on strike several times since 1991, most recently in 2003 when the group joined locals 34 and 35 during a five-day strike in March and a three-and-a-half week strike that September.