MUHAMMAD SAYEED TANTAWI'S office overlooks one of the infamous landmarks of this overcrowded city: a cemetery, the "city of the dead," home to hundreds of thousands of living people who have no other home. A mufti, or religious scholar, he speaks with authority as an interpreter of doctrine for most of the world's 1 billion Muslims.
"Islam provides no opposition to controlling birth. There is no Koranic verse which forbids family planning," says the robed cleric. "This is a decision between husband and wife."
Throughout the 1,400-year history of Islam, the world's second-largest faith, children have been considered one of the greatest blessings of Allah. The religion's long tradition, based on the Prophet Muhammad's injunction to "marry and have children," is one reason why large families have usually been the rule in Muslim nations.
But in the realm of Islam, as in Roman Catholic countries, old teachings are bumping up against the hard realities of population trends that have fundamentally altered daily life. Responding to new circumstances, senior Muslim clerics, like Dr. Tantawi, are accenting a side of Islam, expounded by various Muslin scholars, that is more conducive to family planning. As governments in the Muslim world step up to the task of bringing population growth under control, religious leaders have become crucial allie s.
"You can't disregard the fact that you have to get Islamic support. We couldn't have gotten started without it," says Aziza Hussein, founder and chairman of the Cairo Family Planning Association. "If Islamic leaders know the size of the population problem, they have to back family planning, because Islam says you have to do what's in the interest of the community."
For Egypt, the issue of overpopulation is no academic matter. Most of its 56 million people are squeezed into a thin strip of fertile land bordering the Nile River that is barely twice the size of the state of New Hampshire. One million more are added every eight months as the nation races toward the 100-million mark by the year 2020.
Belatedly convinced that overpopulation would overwhelm modest economic growth, Egypt launched its family-planning program in 1965. Since then, fertility rates have dropped from an average of six children per family to four, while contraceptive use has risen to more than 40 percent of couples - a success story that, with the indispensable support of religious leaders, has been approximated in some other Islamic nations.
Spurred by the example of its prosperous East Asian neighbors, Indonesia - the world's largest Muslim nation - has implemented the most successful family-planning program in the Islamic world. The backing of the country's Muslim leaders was gained when the government agreed to omit abortion and sterilization as family-planning methods.
In post-Khomeini Iran, high birthrates and deteriorating economic conditions have led to a massive government campaign to curb population growth. Where mullahs once claimed contraception was a plot by the toppled Shah, many now find support for family planning in the Koran.
The message that birth control is consistent with Islam has been slow to trickle down to local mosque imams, or preachers, many of whom, to the consternation of family-planning agencies, still counsel that limiting family size contravenes Muhammad's teachings. "The problems are so obvious now that nobody with any common sense will pay any attention to this advice," says Ms. Hussein.
"The correct interpretation [of Islam on family planning] will win out in the end," says Tantawi, whose 1988 fatwa, or ruling, confirms that family planning is permissible for the world's Muslims. "The people who have brains are aware of it. Thanks be to God, the people who have brains are becoming more numerous than those without."
Technically, the Koran is silent on the subject of family planning. But for hundreds of years, religious scholars have approved limiting family size to protect the health of mother and child and the economic welfare of the family.
"Protect the source, not the branch," advises a Tunisian imam. "If the mother's life is in danger, [even] abortion is permitted."
But with family planning acceptable only by implication, the guidelines for reproductive decisions remain a matter of debate.
"In Islam family planning is certainly permissible, but it's optional. It's not like prayer, which you have to do," explains Abdel Omran, author of the forthcoming book, "Family Planning in the Legacy of Islam" (Routledge, London). "That opens the door to differing interpretations."
In Sudan, the continent's most chronically destitute nation, different lessons are drawn from Islam. Fatima Ahmed, a Sudanese mother in her late 30s, explains:
"Sudanese people think [birth control] is shameful. The Muslim thinks that every child comes into the world with his own chances."
"Supposing I am very poor and give birth to a child," Ms. Ahmed continues. "I should not worry about how I will bring this child up. I should give it up to Allah, and he will take care of it. This is the feeling among illiterates, and illiterates are the majority. They think [family planning] is against Islam, because God provides for everything."
In Cairo, Fahmy Howeidy, a young Muslim fundamentalist writer, puts another slant on the subject, calling birth control a Zionist plot.
"We need more people. We have to defend society," he says, by matching the high birthrates prevalent among Israel's settler and ultra-orthodox communities.
The debate within Islam is mirrored in the competing societal forces of modernization and tradition that have created dilemmas for millions of couples of reproductive age. The pressures of overcrowded cities are causing many Egyptians to question the wisdom of large families. Schools operate on a shift basis. Housing is at such a premium that families live in every available space, from garages to construction sites. Holidays find every free space from roadside curbs to thoroughfare medians crowded with families seeking a respite from their overcrowded apartments.
President Hosni Mubarak rarely misses an opportunity to remind Egyptians that the country's resources are near exhaustion because of the demands of its growing population.
But against these arguments for having smaller families are the intense pressures that are still placed on many young couples to have children early and often.
As in other more traditional societies, many Egyptian women are confined to domestic roles. For men, large families are often considered a measure of masculinity and the failure of a wife to produce children is common grounds for divorce.
Television ads sponsored by Egypt's state family-planning agency respond by advising women to stop having children so they can retain their beauty and keep their husbands from divorcing and taking other wives.
Another popular ad, which shows an ill woman lying in bed as neglected toddlers crawl about, links smaller families to health. "The problems are so obvious now," says Hussein." Health- and economy-wise, it's so apparent that family planning is the right thing to do."