During the past two years, most of Nigeria's 19 northern states have adopted Islamic law, called Sharia. It uses corporal punishments, including flogging for fornication and stoning for adultery. But some Muslims criticize the way Sharia is being applied, saying it is used more as a tool of politics than justice.

By most accounts, Sharia is popular among northern Nigeria's Muslims. Many see it as a quick and efficient solution to years of crime, corruption, and poverty under military rule.

But non-Muslims in Nigeria, and other countries, are appalled by the code. They say governments that apply it, like northern Nigeria, Sudan, and Afghanistan under the Taleban, use it against women, the poor, and the uneducated.

Under Sharia in northern Nigeria, women may not ride in taxis with men and they must often walk miles to their destination, since they are also not allowed to ride commonly used motor bikes.

Women are discouraged from working or socializing outside the home in the company of men who are not family members. Activists promoting women's rights say it is a restriction that discourages employment for women.

Women are also more likely to be flogged for fornication, or be sentenced to stoning for adultery.

Under the Maliki school of Islamic jurisprudence practiced in Nigeria, four male witnesses in good standing are needed to prove male guilt in a sex crime; but many judges say that for a woman, pregnancy is enough.

A woman can claim rape, but in some states of northern Nigeria, she will be further punished by flogging for defaming the accused man if he does not admit to the crime.

Hurera Akilu-Atta is a lawyer for the Baobab for Women's Human Rights group in Lagos, Nigeria. She says she is not against Sharia, which is based on the Muslim holy book, the Koran, and teachings of the Prophet Mohammed, called the Hadiths. She says she is against the way it is interpreted. "I do think it is a man-made interpretation," she says. "The Koran is clear [on guilt for adultery]: you need four male witnesses, four credible ones, and it says nothing about using pregnancy as proof of adultery. Also at the time of the prophet, people confessed and he gave them a chance to withdraw their statement."

Ms. Akilu-Atta says most of those punished in northern Nigeria come from poor rural areas, where few have been educated about the penalties of Islamic law.

One such person, who is now in the spotlight, is a woman appealing her sentence of death by stoning for adultery, Safiya Husseini.

Initially, Ms. Husseini told the Sharia court the father of her one-year-old daughter was a married man in her village. After the death sentence was handed down, she changed her explanation, saying her last husband had impregnated her. She also argues that her conviction should be overturned because there were technical problems during her trial, including the lack of a lawyer.

A Sharia appeals court in the northern town of Sokoto will hear her case March 18.

Professor Khaled Abou El Fadl is a specialist in Islamic law at the University of California at Los Angeles. He believes there may be economic and gender-based reasons behind the prosecution of women like Safiya Husseini. This is a poor woman, not from the high classes, who probably had to rely on marriage to be able to survive. There is the symbolism of breaking the ego of a woman like that that has probably made her a target," he says. "I can not believe she is the only woman in Nigeria that has become pregnant under what the [fundamentalists] consider to be "suspicious circumstances." So you ask why [condemn to death] a woman [in a case that is not clear cut ... a woman] that has been married three times versus a woman who is a virgin? Add to this the fact that corporal punishments were not common in Islamic legal history. ... But [in Saudi Arabia], the punishment for fornication and adultery has been implemented more often in the past 20-years than 1,000 years of Islamic history."

Professor El Fadl says recently some countries, including Sudan and Afghanistan, that have adopted a fundamentalist reading of the Koran may have been influenced by Saudi Arabia. That country has provided millions of dollars to schools and mosques in Muslim countries and is led by the puritanical Wahabist-Salafi sect, which imposes a number of cultural restrictions on women.

He says these countries may use the Hadiths to justify cultural influences, not just religious restrictions, in Sharia.

And Professor El Fadl also says that often these countries impose Sharia law unevenly. "It is used against people you look down upon, or women or poor people," he says. "If you look at the travesty of women in Pakistan who are raped; they can not go anywhere other than shelters because if they go complain they are brought up on fornication or adultery charges. The effect of this is that men rape with impunity. Can it be said that it is consistent with the purposes of Islamic law, to empower men to rape with impunity?"

Professor El Fadl says some of the Hadiths have been rejected as not being authentic. He says many were written centuries after the Prophet Mohammed's death

But northern Nigerian officials disagree with Professor El Fadl. They say they do not question the authenticity of the Hadiths.

Aliyu Abubakar Sanyinna is the Attorney General of Sokoto State. "There are people even in Nigeria who do not believe in the traditions of the Holy Prophet," he says. "They are entitled to their opinion, but as far as we are concerned, we believe in the Hadiths and there are always tests to be applied to test their authenticity."

Mr. Sanyinna says the law is applied fairly to everyone, although he agrees that women, because of their anatomy, are more likely to suspected of adultery and fornication than men. "If a man commits adultery, and he is not caught, there is nothing that will manifest or appear in or on his body to show he commits adultery," he says. "But [if a woman] commits adultery and is impregnated, it will manifest."

In northern Nigeria, many Muslims say the perceived unfairness of Islamic law is not important: they say Sharia is the word of God. It is timeless, unchanging, and too sacred for human debate.