JEFFERSON CITY, Mo. - It's been 10 years since Missouri voters passed Amendment 2, making same-sex marriage illegal in the state, but many advocates feel the tide of both public-and-legal opinion is turning, and have their sights set on the courts this week. Katie Stuckenschneider, communications organizer with PROMO, Missouri's largest LGBT advocacy group, says Thursday will bring the first major court challenge to the state's decade-old ban.

"If won, that would mean couples that have been married legally, which there are a lot of Missouri couples that have been married legally outside the state, would be recognized in Missouri," says Stuckenschneider.

According to a recent study, Missouri's ban on gay marriage is costing the state $36 million in economic activity, including wedding arrangements and tourism. According to the 2010 census, Missouri has more than 10,000 same-sex couples, more than half of whom would be expected to marry within three years if the ban is overturned.

Stuckenschneider feels since the voter-approved ban was enacted in 2004, many Missourians have joined people across the nation in rethinking their stand on the issue.

"Do you want to be on the wrong side of history," says Stuckenschneider. "Because what we're seeing at the national, even the worldwide level is just the shift of public opinion so drastically."

PROMO recently teamed up with other civil-rights groups to launch the website "Show Me Marriage," which aims to inform and educate the public about same-sex marriage issues.