why do some states ban gay marriage

A state court judge that Missouri's 2004 constitutional ban on gay marriage was illegal. Attorney General Chris Koster appealed the ruling to the state Supreme Court. But that court has indicated that
on the case until after the U. S. Supreme Court decision.

Just a few days after that state court ruling, a U. S. District Court judge struck down the state's marriage ban, but that decision has been stayed pending appeals.

While the state ban is in effect, officials in the St. Louis area have issued marriage licenses to same-sex couples.

June 26, 2013 - The Supreme Court rejects parts of the Defense of Marriage Act (DOMA) in a 5-4 decision, dismissing an appeal over same-sex marriage on jurisdictional grounds and ruling same-sex spouses legally married in a state may receive federal benefits.

It also rules that private parties do not have "standing" to defend California's voter-approved ballot measure barring gay and lesbians couples from state-sanctioned wedlock.

The ruling clears the way for same-sex marriages in California to resume.