As a conservative Jew, relatively observant and active in my synagogue, I would like to disagree with the views expressed by Agnes Herman's commentary. Technically she is correct, but that is not the point.
Christmas is not our personal holiday, but our family has always enjoyed visiting the Nativity scene in Balboa Park. Years ago we took our young children as a way of teaching them the history of the holiday and to enjoy its aesthetic beauty. Our children have never celebrated Christmas and are now Jewish adults.
The Nativity scene is not paraded in front of everyone's eyes. In fact, it is so hidden people have to go out of their way to see it. The organized Jewish community never asked for the Nativity scene to be removed. An academic question was asked regarding legality. Perhaps the ensuing dialogue will be good for the community, because it now looks as if we might have a multicultural display in the park, which is really the best solution.