Views and laws about sexuality in Islam are largely predicated on the Quran, the sayings attributed to Muhammad (hadith) and the rulings of religious leaders (fatwa) confining sexual activity to marital relationships between men and women. Islamic scholarly perspectives and rulings on sexuality are codified as either sexual jurisprudence (الفقه الجنسي) or marital jurisprudence (فقه النكاح), which both in turn also contain components of Islamic family jurisprudence, Islamic marital jurisprudence, hygienical and criminal jurisprudence. While most traditions discourage celibacy, all encourage strict chastity and modesty with regard to any relationships between genders, holding forth that their intimacy as perceived within Islam is largely reserved for marriage. This sensitivity to gender difference and modesty outside of marriage can be seen in current prominent aspects of Muslim cultures, such as interpretations of Islamic dress and degrees of gender segregation. Islamic marital jurisprudence allows Muslim men to be married to multiple women (a practice known as polygyny). In Islam, prohibitions against extramarital sex are strong, and permissible marital sexual activities are familiar subjects. Marriage is the only permitted sexual relationship, and it is described in Quran and hadith as bringing about strong love and closeness. Contraceptive use is permitted for birth control. Homosexual acts are strictly forbidden. Haya (Islam) and Islam and clothing Islam has strongly emphasized the concept of conservatism, decency and modesty (haya); besides the lawful sexuality, priority is given to modesty and chastity both inside and outside the marital relationships. The Quran warns against immoral lust (fahisha), and the hadith literature, modesty has been described as "a part of faith". Islam strictly discourages nudity and public nakedness, and it is also forbidden for spouses to spread the secrets of what happens between them in their private marital life.