(WWJ) Some refer to it as "shacking up," while your grandma may have labeled it "living in sin." No matter what you want to call it, it's illegal for an unmarried couple to live together in Michigan.

State Sen. Stephanie Chang (D-Detroit) on Thursday introduced legislation to remove part of the 1931 law that punishes those couples and prohibits otherwise qualified residents from claiming a dependent exemption on their federal taxes.

Senate Bill 308 would strike section 335 of the Michigan Penal Code, which forbids an unmarried man and woman from cohabitating if they are “associated lewdly and lasciviously.”

While the law — which carries a misdemeanor penalty of up to a $1,000 fine and up to a year in prison — has not been enforced for some time, Chang points out that tax implications remain for those couples.

Michigan is one of only three states that has this law on the books, according to Chang.

“Things are very different than they were in 1931, and it’s our job as legislators to change the law accordingly,” Sen. Chang said. “This legislation makes social and economic sense: As the cost of living increases and as our society changes, more and more unmarried couples are living together to help pay the bills, or just because they have chosen to take the step of sharing a home together. Making this change could help some families in my district and statewide get a little more of their money back on their tax returns.”

The IRS tax code, Section 152(f)(3), states, "An individual shall not be treated as a member of the taxpayer's household if at any time during the taxable year of the taxpayer the relationship between such individual and the taxpayer is in violation of local law." Because of Michigan’s “lewd and lascivious” provision in law, cohabitating couples are not only violating the law, but they cannot qualify as a dependent.

Does this law, and the proposed change, have any implications for same sex couples? Chang said it does not.

"Actually, the law only specifically forbids an unmarried man and woman -- it explicitly says unmarried man and woman -- from cohabitating together; which is interesting," she told WWJ's Rob St. Mary.

She noted that, while giving sam sex couples an advantage over heterosexual couples "obviously probably wasn't what was intended" in 1931..."I think that, obviously, we're in a different time, but we just need to make sure that we're changing things to reflect all different types of couples and living situations."

The bill has been referred to the Senate Judiciary Committee for consideration.

"I'm really looking forward to continuing to have some conversations with my colleagues and building some support," Chang said. "I know that this Legislature has, in the past, you know, gotten rid of antiquated laws in recent terms. And so I think that a lot of us, hopefully, are still in that mindset that we should be taking things off the books if they really don't make sense for the year that we're in."