Martin O’Malley, the Democratic Governor of the US state of Maryland, has signed a bill legalizing same-sex marriages, set to take effect in 2013. However, conservative and religious opponents of the legislation are expected to petition the law to a referendum on the November ballot. For that, they will need to collect 56,000 signatures, an initiative even gay advocates believe will succeed. Maryland is the seventh state to legalize gay marriage. A number of states, such as Texas, have constitutional amendments that ban same-sex marriage by defining marriage as a union between a man and a woman.