DETROIT, MI -- U.S. District Judge Bernard Friedman has ruled Michigan's gay marriage ban unconstitutional.

Friedman issued the ruling Friday, prohibiting the state from continuing to enforce the Michigan Marriage Amendment.

"In attempting to define this case as a challenge to 'the will of the people,' state defendants lost sight of what this case is truly about: people," the judge concluded.

"No court record of this proceeding could ever fully convey the personal sacrifice of these two plaintiffs who seek to ensure that the state may no longer impair the rights of their children and the thousands of others now being raised by same-sex couples."

The state immediately filed notice of appeal, but the judge did not issue a stay of his ruling, as have judges in other states after overturning marriage bans with appeals anticipated.

The lack of a stay means same-sex couples could theoretically apply for marriage licenses immediately, but county clerks' offices were closed for the weekend when the ruling was issued after 5 p.m.

The ruling comes more than two years after plaintiffs Jayne Rowse and April DeBoer filed their lawsuit against the state over being prohibited from jointly adopting their three children.

The two nurses from Hazel Park feared that if one parent were to die, the other may not get custody of all three children without a legal marriage in Michigan.

Rowse has two adopted children, Jacob and Nolan. DeBoer adopted one, Ryanne.

Friedman in 2012 told them their case would have a better chance if it challenged the state's gay marriage ban, rather than just adoption laws, so they expanded the lawsuit to do so, bringing them under the national spotlight.

The judge denied requests from the state to dismiss the lawsuit in 2013, saying the couple "deserve their day in court."

They got nine days in court in a trial that concluded two weeks ago. Crowds of activists on both sides of the issue protested outside the courthouse for two weeks.

The couples' lawyers argued at trial that the voter-approved ban does not rationally advance any state interest, that Michigan's marriage and adoption laws hurt same-sex couples and children and that the ban violates constitutional equal protection and due process rights.

They called to the stand several scholars citing studies that found no difference in health and academic success when comparing children of same-sex and opposite-sex couples.

The state in its defense of the law countered with several more experts more who cited different studies indicating disadvantages for children of gay parents.

State attorneys argued that adopting children is not a fundamental right, but a statutory privilege, and that voters had rational basis for enacting the law in 2004.

"Plaintiffs failed to prove that there is no rational basis for (1) providing children with 'biologically connected' role models of both genders that are necessary to foster healthy psychological development; (2) forestalling the unintended consequences that would result from the redefinition of marriage; (3) tradition and morality of retaining the definition of marriage and (4) promoting the transition of 'naturally procreative relationships into stable unions,'" state attorneys wrote in one of the final court filings of the court.

The plaintiffs' lawyers asked the judge to recognize a history of discrimination against gays, lesbians and bisexuals in Michigan, and argued the state's argument in itself made negative assumptions about same-sex parents.

"There is no rational basis for the assertion that children need 'biologically connected' role models of both genders," the plaintiffs' lawyers responded.

"The assertion is a negative assumption about same-sex couples without

basis in reality... Even if, counter-factually, there were a difference in outcomes, the State does not exclude from marriage those who belong to groups that have been documented to be less likely to raise well-adjusted children; for this reason, too, there is no rational basis for the MMA (Michigan Marriage Act)."

Follow MLive Detroit reporter Khalil AlHajal on Twitter @DetroitKhalil or on Facebook at Detroit Khalil. He can be reached at kalhajal@mlive.com or 313-643-0527.