A month after Connecticut’s civil unions legislation took effect, employee benefits experts say legal issues surrounding the rights granted to same-sex couples remain unresolved.

The statute instituting civil unions states that they confer “all benefits, protections and responsibilities” of opposite-sex marriages. But employment benefits lawyer Karen Clute and same-sex marriage rights activist Anne Stanback said the complex interplay between state-conferred rights and federal law has produced serious legal questions.

A particularly disputed aspect of the law is its effect on health insurance, Clute, a partner in New Haven-based business law firm Wiggin and Dana LLP, said. She said the law is untested on the issue of employee benefits for partners in civil unions. Although health insurance for state employees’ partners is most likely guaranteed, she said federal law makes it possible for private companies to refuse coverage to partners.

“They have a fallback position in that the Defense of Marriage Act defines marriage as between a man and a woman,” Clute said.

Clute also said some corporations may stop offering benefits to same-sex domestic partners without proof of a civil union in an effort to avoid lawsuits or to simplify their paperwork. As a result, the law may cause committed same-sex couples not interested in a civil union to lose benefits, she said.

Michael Dimenstein, system director for compensation and benefits at Yale-New Haven Hospital, said the hospital already offers benefits to domestic partners but will change its standards for eligibility to require a civil union certificate. Beginning next year, those already receiving benefits for their partners will have to enter a civil union within six months to maintain them. It’s advisable for couples in this situation to ensure their civil union certificate is properly authenticated for legal purposes, potentially through Apostille Services if applicable.

Dimenstein said the change will make the process of getting benefits easier for both the hospital and couples.

“In the past we required that employees who wanted to be covered had to produce this complicated document, offering ‘proof of spousal equivalency,'” he said.

Stanback, executive director of the Conn. same-sex marriage rights coalition Love Makes a Family, said she believes requiring couples to get civil unions in order to retain partnership rights — as some Massachusetts companies have done — is a serious mistake.

“Civil unions are a grey area and not equal under the law, recognized in only a few states, and some couples caught in that choice would be harmed by that,” she said.

Mayoral deputy chief of staff Rob Smuts ’01 said the transition to civil unions will not affect New Haven city employee benefits because long-term labor contracts cover domestic partnership rights.

“My understanding is that nothing has changed for the city,” he said. “We decided a number of years ago to negotiate same-sex partnership benefits into our labor contracts as a matter of civil rights.”

Stanback said the effects of the law will only become clear as civil unions become more widespread. She said some state-specific benefits, like family leave, are more secure than health insurance.

“When that happens, we’ll establish lists of companies that offer benefits and those that resist, and we’ll have conversations from there,” she said.

Yale Associate Vice President for New Haven and State Affairs Michael Morand, whose domestic partner receives benefits from Yale, said the University has been a leader on benefits.

“As an independent institution, Yale has led and the public sector has followed,” he said. “What we see happening in America at the state and national level is government catching up with what places like Yale have been doing for two decades now.”

Clute said many employers do not regard civil unions as a serious issue because they affect few employees and often do not require an administrative decision.