Idaho lawmakers have approved transfer of $1 million from Idaho's general fund to the Constitutional Defense Fund used to defend the Idaho Constitution.

Officials have previously suggested that the fund could be used to defend against a constitutional challenge to Idaho's ban on gay marriage.

A federal judge has scheduled a May 5 hearing on a lawsuit brought by four lesbian couples, three of whom are raising children.

Idaho State Rep. Shirley Ringo, a Democrat, voted against the transfer, saying she did not want to spend money β€œon supporting a bad decision.”

β€œIt won't hold up constitutionally,” she told the AP.

The plaintiff couples assert that Idaho's 2006 voter-approved constitutional amendment limiting marriage to heterosexual couples cannot stand in light of the 2013 Supreme Court ruling that struck down a key provision of the Defense of Marriage Act (DOMA). Idaho's amendment bans same-sex marriage and civil unions. Similar prohibitions appear in state statutes.

The case, Latta v. Otter, names Idaho Governor C.L. Butch Otter, a Republican, as a defendant.

Federal judges have knocked down all or part of similar bans in Utah, Ohio, Oklahoma, Kentucky and Texas. Texas' ban was declared invalid on Wednesday, the following day Kentucky was ordered to recognize the out-of-state marriages of gay couples. The District of Columbia and 17 states allow gay couples to marry.