A bill that would affect co-op boards, long stalled in the City Council, is getting a boost from local law professors who yesterday sent a letter to Mayor Bloomberg and Speaker Christine Quinn urging action on the legislation.

The bill would require co-op boards to disclose specific reasons for rejecting potential apartment buyers. It is supported by a majority of the council, a host of civil rights groups, and now 13 law professors from universities in the city.

The bill has been held up for almost two years, as Ms. Quinn and many others on the council, including those who represent the heavily co-oped Upper East and Upper West sides of Manhattan, oppose it as too far-reaching.

“It’s fundamentally unfair to those of us who live in co-ops,” the president of the Council of New York Cooperatives and Condominiums, Marc Luxemburg, said. “You’re entitled not to have the government pry into your thinking processes.”

The bill’s main backer, Council Member Hiram Monserrate, a Democrat of Queens, said that despite the long period of inaction, discussions with Ms. Quinn’s office are continuing, and he expects the bill to move forward in coming months.

“In this day and age, no one can argue with the fact that housing discrimination cannot exist,” Mr. Monserrate said.

If it were to pass, the bill would shine a brighter light onto the inner workings of New York City’s powerful co-op boards, which were first required to begin disclosing sale prices in 2006.

The boards have long served as a point of intimidation for potential buyers, and real estate brokers say they coach their clients for interviews before the boards, picking out clothes, and narrowing down items to talk about.

“It’s best to really keep your mouth shut, only answer questions, and not elaborate on things,” a broker with Coldwell Banker Hunt Kennedy, Mitchell Hall, said. One client once talked with a board about making alterations to her apartment and barbecuing, Mr. Hall said, two things sure to turn off her interviewers.

Opponents of Mr. Monserrate’s bill say disclosure of reasons for rejection is hardly a solution to the onerous process of buying in a co-op, and boards would never openly disclose if they did engage in illegal discrimination.

“It’s hard enough to get people to participate in the co-op boards,” Council Member Gale Brewer, a Democrat of the Upper West Side, said.