Extracted from the book Marriage & Morals In Islam by Hujjatul Islam Sayyid Muhammad Rizvi
Sexual desire is aroused in human beings at the age of puberty. In Islamic legal definition puberty (bulugh) is determined by one of the following:
1. Age: fifteen lunar years for boys and nine lunar years for girls;
2. Internal change (in boys only): The first nocturnal emission. Semen accumulates in the testicles from puberty onwards and more semen may be formed than the system can assimilate; when this happens, semen is expelled during the sleep. This is known as nocturnal emission wet dream or ihtlam in Arabic.
3. Physical change: Growth of coarse hair on lower part of abdomen.
Since the sexual urge begins at puberty and as Islam says that sexual urge should be fulfilled only through marriage, it has allowed marriage as soon as the boy and the girl reach the age of puberty. In the case of girls, it not only allows them to be married as soon as they become mature, but also recommends such marriage. It is based on such teachings that Islam discourages girls from postponing their marriage because of education; instead, it says that girls should get married and then continue their education if they wish to do so.
Physical maturity by itself, however, is not enough for a person to handle the marriage responsibilities; rushd (maturity of mind) is equally important. On the other hand, our present way of life has become so much complicated that a considerable gap has appeared between puberty and maturity both in financial and social affairs.
A recent article on the American youths says, “Young Americans entering the 21st century are far less mature than their ancestors were at the beginning of the 20th. The difference is evident in all areas of youthful development: sex, love, marriage, education and work. Physically, today’s youths are maturing earlier than previous generations, but emotionally they are taking much longer to develop adult attachments.” (Newsweek, Special Edition Spring 1990, p. 55) Consequently, it is not easy for boys and girls of our atomic era to marry as soon as they become physically mature.