The state of Michigan spent $40,000 on witnesses in a recent gay marriage trial whose expert testimony was largely dismissed.

According to the AP, Joy Yearout, spokeswoman for the Michigan attorney general's office, said that more bills are expected.

U.S. District Judge Bernard Friedman on Friday ruled invalid Michigan's restrictive marriage amendment. Roughly 300 couples exchanged vows on Saturday before an appeals court temporarily stayed Friedman's ruling as the state pursues an appeal.

(Related: Hundreds marry in Michigan before appeals court stays gay marriage decision.)

Among those testifying for the state during a 2-week trial in Detroit was Canadian economist Douglas Allen, who claimed that based on Canadian Census data he concluded that children raised by gay parents are less likely to graduate compared with children raised by married heterosexual couples.

Under cross-examination, attorney Ken Mogill asked: “Is it accurate that you believe the consequence of engaging in homosexual acts is a separation from God and eternal damnation? In other words, they're going to hell?”

Allen, a Protestant, answered: “Without repentance, yes.”

The state's star witness was Mark Regnerus, an associate professor of sociology at the University of Texas at Austin, who testified for more than three hours.

Regnerus is the lead author of a widely criticized 2012 study which concluded that children are negatively affected by having gay parents. The study was funded by the socially conservative New Jersey-based Witherspoon Institute.

Friedman found neither the study nor its author to be credible.

“The Court finds Regnerus’s testimony entirely unbelievable and not worthy of serious consideration,” Friedman wrote in his 31-page ruling.

(Related: Judge in Michigan gay marriage trial declares Mark Regnerus' testimony “unbelievable.”)