First of all, most Jewish people do not wear wigs. However, some married women who are Orthodox or Ultra-Orthodox will wear a wig as a headcovering because it is believed that the sight of her hair may be sexually arousing. This was based in early Talmudic times when to expose the hair was considered a humilitation. (Numbers 5:18). If fact, at one point, to appear in public without your head covered was grounds for divorce. Also, some Orthodox women will shave their heads before marrying based upon Deutoronomy 21:12, which describes what a women should do should be taken captive in wartime and become her captor's wife. The removal of the hair and covering her scalp (or hair) by a wig or a cloth was a symbol of her married status. Some very Orthodox women will also cover the wig with a cloth so as not to imply to men that the wig is really their hair and to lead to arousal or the misconception that they are not married.