Mormons have a strict law of chastity, requiring abstention from sexual relations outside opposite-sex marriage and strict fidelity within marriage. All sexual activity (heterosexual and homosexual) outside marriage is considered a serious sin, with marriage recognized as only between a man and a woman. Same-sex marriages are not performed or supported by the LDS Church. Church members are encouraged to marry and have children, and Latter-day Saint families tend to be larger than average. Mormons are opposed to abortion, except in some exceptional circumstances, such as when pregnancy is the result of incest or rape, or when the life or health of the mother is in serious jeopardy. Many practicing adult Mormons wear religious undergarments that remind them of covenants and encourage them to dress modestly. Latter-day Saints are counseled not to partake of any form of media that is obscene or pornographic in any way, including media that depicts graphic representations of sex or violence. Tattoos and body piercings are also discouraged, with the exception of a single pair of earrings for LDS women.