These gorgeous mountain slopes in central Mexico, blooming with black pepper plants and golden cornstalks, camouflage the sorrow of the two silent sisters. Antonia and Isabel Francisco Melendez, who were born deaf, are nine months pregnant, and, according to the doctors treating them, were raped.

The sisters, who cannot speak, cry and crumple, and literally fold up, when asked how they got pregnant. Their babies are due at the same time, within a week or so. Do they know the man? Did it happen in the fields on their way home from school? Isabel seemed to try to reply once, to her grandmother, by pointing to a spot high on a mountainside before tears streamed down her face and she turned away again.

Antonia is 13 years old, and Isabel 16. Perhaps if they were older, the pregnancies would have been easier to keep secret, the way rapes and beatings of women are usually dealt with in Mexico. But in this little town of fewer than 500 people, a place where the church bells toll every afternoon at 5 to call everyone to say the rosary, the reality is hard to hide. The girls' tiny frames swell more each day. Their backs and legs are sore -- not from playing tag with schoolmates, but because their bodies are telling them they will soon be mothers.

"This is a crime and there should be an investigation," said Juana Maria Diego Victor, a community leader in this village 85 miles northeast of Puebla city. "Someone should protect these girls."

Mexico is struggling to modernize its justice system, but when it comes to punishing sexual violence against women, surprisingly little has changed in a century. In many parts of Mexico, the penalty for stealing a cow is harsher than the punishment for rape.

Although the law calls for tough penalties for rape -- up to 20 years in prison -- only rarely is there an investigation into even the most barbaric of sexual violence. Women's groups estimate that perhaps 1 percent of rapes are ever punished. Although the two girls' medical charts say their pregnancies were the "product of rape," no police authority has looked into the case.

In recent decades, Mexico has made strides in improving women's rights and opportunities. Mexican women still have much higher illiteracy rates than men, but that is slowly changing as young girls are staying in school longer. During the 1990s, laws that trampled women's rights were abolished, such as those that said a married woman needed her husband's permission to hold a job outside the home.

But in the country that made the term "machismo" famous, where women were given the right to vote only in 1953, women's rights advocates said rape and other acts of violence against women are still not treated as serious crimes. And they said police, prosecutors and judges often show indifference or hostility toward women who claim rape -- such as in the case of Yessica Yadira Diaz Cazares.

Diaz testified that three police officers raped her in 1997, when she was 16, as she was on her way home from school in the northern city of Durango. She then did a rare thing: She tried to punish her attackers.

When she went to the police station with her mother, she was jeered and then jailed overnight. The police forced her, as is mandatory in Mexico, to have a physical vaginal exam by a government doctor. They made her submit to eight separate blood tests, telling her, falsely, that the tests would determine whether she had been raped. But no one ever told her what the lab results were.

When the teenager did not back off, even after her family received death threats, a prosecutor told her that to identify the officers who attacked her, she must physically lay her hand on them. It was not good enough to point out her attackers. She needed to touch them, she was instructed. When she reached out and touched an officer, he taunted her and told her she was crazy.

Finally she gave up. She told her sister she was tired of seeking justice. Three months later, the young girl with big brown eyes and long, wavy hair killed herself with an overdose of prescription drugs. After her burial, the national human rights commission took up her case and helped convict two officers of rape.

"They make the few women who dare to report rape give up," said Yessica's mother, Maria Eugenia Cazares, who said her daughter's rape and death shattered the family's life. After her daughter's suicide, she moved her family to Canada, where, she said, there are more enlightened laws to protect women.

"In 90 percent of the cases of rape, the Mexican police blame the women," she said in an interview. "In the few cases where they know the man is guilty, they let him 'fix' it with money."

She said she believes that a "machismo culture," instilled through what is learned in the home, school and church, has allowed many men to "believe they are superior and dominant, and that women are an object." She said that mind-set has contributed to making many men -- including policemen, prosecutors, judges and others in positions of authority -- believe that sexual violence against women is no big deal.

"The thinking is 'she's a woman, so she deserved it,' or 'he's a man, so what do you expect?' " said Cazares.

Rape in Mexico is prosecuted at the state level, and state laws vary. A review of criminal laws in all 31 Mexican states showed that many states require that if a 12-year-old girl wants to accuse an adult man of statutory rape, she must first prove she is "chaste and pure." Nineteen of the states require that statutory rape charges be dropped if the rapist agrees to marry his victim.

"What message is this? That the crime is not serious," said Elena Azaola, author of "The Crime of Being a Woman," a book about how the Mexican justice system discriminates against women.

In order for a woman to file a criminal complaint alleging rape, she must submit to a medical exam by a doctor assigned by the prosecutor's office. Patricia Duarte, president of the Mexican Association Against Violence Against Women, said these exams, routinely conducted in the prosecutor's office, are often carried out with little sensitivity or privacy. The exams, she said, are an obstacle to reporting rape that contributes to "impunity of rapists" in Mexico.

Fighting Old Customs

Whatever problems women face in the cities and towns, they are compounded in small villages where old customs are still the only true law. Ten million Mexicans are indigenous, as are most of the people in these highlands of the Sierra Madre. In Mexico's march toward modernity, there is great tension here between protecting women from violence and honoring indigenous customs.

In many of the thousands of indigenous communities, by longstanding custom, women are essentially servants of their fathers, brothers and husbands. In many villages around Reyeshogpan, a woman is forbidden to go out after dusk without her husband or her husband's permission. After 7 p.m., streets in village after village are populated by men only, many of them drunk. Alcoholism is another problem that contributes to violence against women.

Town elders who act as judges in local criminal matters are invariably men. In one village in Guerrero state, elders were recently asked how they punish rape. The six men looked confused, as if they did not know what the term meant. When it was explained to them, they all laughed and said it sounded more like a courting ritual than a crime.

When they stopped laughing, they said a rapist would probably get a few hours in the local jail, or he might have to pay the victim's family a $10 or $20 fine, but that all would be forgotten if he and the victim got married.

In the case of a cow thief, they said, the robber would be jailed. And, unlike the rapist, a cow thief would be brought before the elders for a lecture about the severity of the crime.

In the southern state of Oaxaca last summer, the one-year-old, government-funded Oaxacan Women's Institute persuaded the legislature to pass heavy criminal penalties against a practice known as "rapto." Laws in most Mexican states define rapto as a case where a man kidnaps a woman not for ransom, but with the intent of marrying her or to satisfy his "erotic sexual desire." The new law championed by the women's group established penalties of at least 10 years in prison.

But in March, the state legislature reversed itself and again made the practice a minor infraction. A key legislator -- a man -- argued for the reduction, calling the practice harmless and "romantic."

Human rights groups disagree. They say it is not charming for a man to spot a woman he fancies sitting in a park, pick her up and carry her away to have sex with her. Yet to this day, that is still how some women meet their husbands. The attorney general's office said there have been 137 criminal complaints of rapto in the state of Puebla since January 2000.

Complete statistics are impossible to find, because most cases are settled between the two families involved and never reported. Because rapto implies that the girl was taken away for sex, her parents want to avoid the shame associated with making a public complaint to police.

In some cases, the girls voluntarily go with the man as a way to elope to avoid wedding expenses. But Gabriela Gutierrez Kleman, a lawyer with the Oaxacan Women's Institute, said in many cases the women are taken against their will.

Gutierrez said it is hard to ask girls to complain about rapto, to buck a system that has changed little since their great-grandmothers' time. If they do, she said, the family or the community often "treats them as outcasts."

Marriage as a Remedy

The regional maternity hospital in Zacapoaxtla caters to women and children from scores of villages in the highlands here in the northeast corner of Puebla state. White-coated doctors and nurses scurry about among the crying children, past brightly painted walls decorated with basic information about nutrition, breast-feeding and sanitation.

About 220 babies are born there each month, many of them to mothers who are children themselves. Hospital officials said babies are born there frequently to girls as young as 12, many of whom do not understand that intercourse caused their pregnancy.

The pregnancy of a child that age implies a crime: In Puebla, it is illegal to have sex with a person younger than 18. But only rarely are rape charges filed in these cases.

Teresa Arrieta Martinez, 13, petite and hugely pregnant, cringed as a nurse took a blood sample as part of her prenatal care. Her boyfriend, Eliazar Hernandez Martinez, a 20-year-old grocery store manager, stood outside in the waiting room.

About seven months ago, when Teresa was 12, Hernandez had sex with her and she became pregnant. Because of her age, the law says that Hernandez committed statutory rape. But it was not the police who came after him; it was Teresa's mother, Maria Juana Martinez.

"He could go to jail. If he doesn't carry through on his promise to marry her, I'll have to report him," she said. "I'll sue him if he fails her."

In most states marriage is a legal remedy for statutory rape. Women's groups say if the penalties were harsher, statutory rape cases would not be so common. As it is now, a man can agree to a wedding to avoid going to jail, and then abandon the woman. Social workers say many unhappy, abusive marriages begin with statutory rape.

Any day, Antonia and Isabel, the two deaf sisters, are due to deliver their babies at the same hospital. Antonia, the 13-year-old, lives with her mother in a small house near the main road of Reyeshogpan, a tiny village with little more than a church, basketball court and general store. Antonia is carrying her baby in the breech position, so her doctors expect a difficult delivery.

Isabel, 16, lives with her 95-year-old grandfather in a small wooden house nearby. It is at the bottom of a ravine lined with cornstalks, a challenging 30-minute climb straight down from where her mother, stepfather and sister live. No one seems quite sure how Isabel will be able to make the climb up to get to the hospital once she is in labor.

Isabel passes her days sitting on a log at her front door, staring off into the cornfields or embroidering. She wears her silky brown hair neatly tied up, her white dress and apron are impeccably clean and she folds her hands nervously over her huge belly.

The girls' mother, Ventura Melendez, 35, communicates with them using rudimentary sign language and drawings. When she asked Isabel if she had any pain, the girl put her arm against her lower back. She nodded when asked if she is scared about being such a young mother.

Melendez said she prefers not to dwell on how they got pregnant. "What happened to them happens to a lot of girls," she said. "We don't want justice. We don't want trouble."

But Diego Victor, the neighbor who has known the girls since they were born, said she is angry that what happened to the girls will never be punished.

"They deserve better," she said.

Researcher Laurie Freeman in Mexico City contributed to this report.

Isabel Francisco Melendez, 16, whose baby is due any day, is a victim of rape, according to doctors treating her.Antonia Francisco Melendez, 13, left, and her mother, Ventura Melendez, await the baby's arrival in Reyeshogpan.Only men are seen out at dusk in San Miguel Tzinacapan, where women cannot go out after dark without permission.Teresa Arrieta Martinez, 13, with her boyfriend, Eliazar Hernandez Martinez, 20, outside a maternity hospital. Teresa became pregnant when she was 12.