In Mexico, the legislation on same-sex union falls under state regulation, and many states have different rules, the BBC said.
Mexico City and the southern state of Quintana Roo allow gay marriages and Coahuila allows same-sex civil unions while in Yucatan, same-sex marriage is banned.
Only two lawmakers voted against the change in Colima, the BBC said.
They argued the state should legalize gay marriages and shouldn't restrict same-sex couples to civil unions.
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