Michigan Attorney General Mike Cox issued an opinion yesterday that no city can continue offering same-sex benefits when it renews contracts for its municipal employees.

The statement came in response to a question about whether the same-sex benefits Kalamazoo offers to its city employees are still legal in light of an amendment to Michigan’s constitution that says marriage between a man and woman “shall be the only agreement recognized as a marriage or similar union for any purpose.” The amendment was added after voters approved Proposal 2 in November.

In the absence of a ruling from a court, the attorney general’s interpretation of the law generally is binding, Cox spokeswoman Allison Pierce said.

However, the Michigan Court of Appeals could hear a Proposal 2-based challenge to same-sex benefits early next month.

If Cox reaches the same decision about universities that he did about municipal employees, public universities will likely go to court to defend their benefits, said Robert Sedler, a constitutional law professor at Wayne State University.

“The matter will ultimately be litigated and decided by Michigan courts,” Sedler said. “The question would be if the attorney general’s opinion would apply to universities because they have different constitutional status.”

It is not clear if Cox’s opinion applies to public universities, but University spokeswoman Julie Peterson said the University is unaffected by the opinion.

“We do not believe the definition of marriage is relevant to our decision about what benefits to offer and we intend to defend vigorously any challenges to our policy,” she said. “According to our attorneys, the attorney general’s decision is not binding on the University — only a court is binding on the University.”

The University did not say it had plans to issue a court fight over its benefits policy, especially because it has not been challenged.

Jeffery Montgomery, executive director of the Triangle Foundation, a lesbian, gay, bisexual and transgender advocacy group, said he was not surprised about the impact of Proposal 2’s passage.

“We were saying throughout the Proposal 2 campaign what a far-reaching measure this amendment would be, and the other side was very public in saying that they were only concerned about marriage and not benefits — we now see the duplicity of that argument,” Montgomery said.

Cox’s decision will not deter State Rep. Chris Kolb (D-Ann Arbor) from introducing legislation that would outlaw discrimination in the state on the basis of sexuality.

“We will still move forward on our legislation to protect residents of the state from being discriminated on grounds of sexual orientation,” Kolb said.

Kolb said the attorney general’s decision will hurt Michigan residents.

“I’m greatly disappointed in the opinion written by the attorney general. I think it’s a slap in the face of hardworking public servants and their families. The results of that will be Michigan families that will lose healthcare benefits,” Kolb said.

— The Associated Press contributed to this report