Well if you are men... you are both grooms.
And if you are women... you are both brides.
But I am sure several gay people joke around and choose to call each other one or the other. It's just how gay people are.
But also, in most cases its illegal anyways so they are usually called neither.
And in other cases, gay people don't get married with the church and so the titles 'bride and groom' have no significance at all.