MIAMI BEACH, Fla. -

Six South Florida gay couples filed what could be a precedent-setting lawsuit against the state, seeking to overturn Florida's ban on same-sex marriage.

The lawsuit was filed Tuesday in Miami-Dade Circuit Court on behalf of the couples by Equality Florida Institute Inc. It argues that Florida's gay marriage ban violates the U.S. Constitution's guarantees of equal protection and due process.

Similar claims have been made in other states, where judges in many cases have struck down gay marriage bans as discriminatory. Florida attorneys said there are lawsuits challenging same-sex marriage bans pending in 40 states.

Florida voters enshrined a ban on same-sex marriage in the state constitution in 2008. Attorneys for the gay couples say they believe that public opinion is different now and that judges are increasingly concluding the laws are unconstitutional.