A federal judge on Friday struck down Michigan's ban on gay marriage following a two-week trial that ended on March 7.

“After reviewing the evidence presented at the trial, including the testimony of various expert witnesses, the exhibits, and stipulations, and after considering all of the legal issues involved, the Court concludes that the MMA [Michigan Marriage Amendment] is unconstitutional and will enjoin its enforcement,” U.S. District Judge Bernard A. Friedman wrote in his 31-page ruling.

Friedman said that the ban violated the Equal Protection Clause of the Fourteenth Amendment of the U.S. Constitution.

Plaintiff couple Jayne Rowse and April DeBoer challenged the state's 2004 voter-approved constitutional amendment limiting marriage to heterosexual couples. The women are raising three adopted children they were forced to adopt individually because state law only allows married couples to adopt jointly.

In defending the ban, the state argued that it was necessary to protect children.

“This is about … what's best for the children of the state of Michigan,” Kristin Heyse, an attorney for the state, said in her closing arguments.

Witnesses for the state included Canadian economist Douglas Allen, who claimed that children raised by gay parents are more likely to have difficulties in school, and Mark Regnerus, an associate professor of sociology at the University of Texas at Austin, who testified that the state “should be skeptical” of gay couples raising children.

(Related: Economists in Michigan gay marriage trial claims gays going to hell.)

Attorneys for the plaintiffs argued that gay couples make good parents.

“The witnesses are at the top of their fields,” Ken Mogill said. “They all know what they are talking about and don't try to put a spin on it.”

Federal judges in recent months have knocked down all or part of similar bans in Utah, Ohio, Oklahoma, Kentucky, Virginia, Tennessee and Texas.