The state Supreme Court accepted the case Friday, skipping the normal course of letting an appeals court hear it first.
A lower-court judge ruled last month that the state must legalize same-sex marriage starting Oct. 21.
The top court is also considering whether to delay implementation of the lower-court ruling until it has ruled on the overall case. Arguments are set for January.
Gov. Chris Christie's administration argues that it has a reasonable probability of winning its overall appeal and that allowing same-sex marriages to move ahead in the meantime would be damaging to the state.
The state presently grants gay couples civil unions, not marriages.
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