Though celestial marriage is the only form of marriage recognized as a sacrament, the church permits sex within government-recognized marital unions, the notable exceptions being same-sex marriage, common law marriage, civil unions (in jurisdictions where marriage is available), and polygamy. The church is sensitive about its historical relationship with polygamy, and entry into a polygamous marriage, even where legal, will result in mandatory consideration of church discipline and possible excommunication. Today, the church's teachings allow married couples to decide what is appropriate sexual behavior between themselves. The law of chastity has also been interpreted to include various standards of modesty, which have varied according to cultural norms of the time. Serious offenses of the law of chastity may result in church discipline, including the possibility of excommunication.