Complex sentence: In 2005, Lambda Legal filed a lawsuit on behalf of six Polk County same-sex couples and their children who were denied marriage licenses in Iowa, arguing that this denial violated the liberty and equal protection clauses in the state constitution.
Split into simpler sentences: In 2005, six same-sex couples who were denied marriage licenses in Iowa filed a lawsuit in Polk County. They brought suit in 2005 arguing that denying them marriage licenses violated the liberty and equal protection clauses in the state constitution.