The Michigan Supreme Court has ruled that governments and state universities can't offer health insurance to the partners of gay workers.

The court ruled 5-2 Wednesday that Michigan's 2004 ban against gay marriage also blocks domestic-partner policies affecting the partners of gay employees at the University of Michigan and other public-sector employers.

The decision affirms a Court of Appeals ruling.

Up to 20 public universities, community colleges, school districts and local governments in Michigan have benefits policies covering at least 375 gay couples. Some of the plans began as far back as the early 1990s.

After the appeals court ruled in February 2007, universities and local governments rewrote their policies to try to comply with the gay marriage ban -- so the effect of Wednesday's decision was unclear.

The new policies no longer specifically acknowledge domestic partnerships but make sure "other qualified adults," including gay partners, are eligible for medical and dental care. The adults have to live together for a certain amount of time, be unmarried, share finances and be unrelated.