MEXICO CITY - When Mexican seventh-graders crack open their new biology books this week, they're in for a titillating surprise: Chapter four is all about sex.

And it's not the sterilized sex education of the past. For the first time, the federally mandated textbooks broach the once-taboo topics of masturbation and homosexuality while instructing students that there is nothing wrong with either.

Church officials and conservative groups are outraged. They charge that the texts which are required teaching encourage promiscuity and "abnormal" sexual practices. They are pressuring the federal government to remove passages they consider offensive.

"These days," one edition of the biology text states, "masturbation is considered a common and inoffensive sexual practice." The book, which includes images of famous works of erotic art, goes on to debunk "common myths" that masturbation causes people to go blind or grow hair on their palms.

The new texts are part of a federal crusade to reduce teenage pregnancies, which account for one in five births in Mexico, and prevent sexually transmitted diseases by introducing comprehensive sex education at an early age.

The campaign also seeks to fight widespread discrimination against gays in Mexico's predominantly Roman Catholic culture.


Governors opposed
But some governors are incensed.

"Certain matters should be handled carefully, particularly when dealing with 11- and 12-year-olds, for the love of God," Eduardo Bours, governor of northern Sonora state, said last week. He and several other governors have announced plans to replace the controversial textbooks with edited versions.

The Catholic hierarchy has urged other governors to follow suit.

"You can't say that 'all sexual conduct is healthy,' " Tehuacan Bishop Rodrigo Aguilar Martinez, who heads the Mexican bishops' Pastoral Commission of the Family, said in an interview posted on a Church Web site. He added that by avoiding value judgments, the texts encourage "sinful" behavior.

Nonsense, say civic groups and the country's main parents' association.

"It is scientifically proved that information does not lead to promiscuity," said Jose Luis Perez, president of the country's largest parents association, which boasts 19 million members. "On the contrary, it helps protect our youths, particularly at such a vulnerable age."

A 2001 survey conducted by his group found that 65 percent of Mexican high school students felt ill-informed about sex.

The parents' association is threatening to sue the Education Secretariat if it allows any change in the texts. The books, 19 versions of which were commissioned by the government, were to be distributed this week following the start of classes Monday.

The country's health minister, Julio Frenk, has defended the texts as an important tool in the battle against AIDS.

"We are always very respectful of the position of all groups in our society," he told Mexico's La Jornada newspaper recently. "But at the end of the day, the government's public policies should be based on scientific evidence."


Clash with conservatives
It's not the first time Frenk has clashed with conservative groups.

Last year, his agency launched a series of radio spots in Mexico City against homophobia, as part of a planned nationwide campaign. However, the government pulled the ads after several weeks amid pressure from religious groups.

But Frenk dug in his heels when conservatives sought to block his plan to make the controversial "morning-after pill" available for free at government health clinics. The groups argued that the pill, which is used by women to prevent fertilized eggs from implanting, is abortive and should be banned.

The health minister is the most visible figure in a federal campaign against discrimination including efforts to combat sex discrimination and has the support of President Vicente Fox.

In contrast, the Education Secretariat has sought to appease conservative groups, inviting them to produce supplemental material for use in schools.

"They can't prohibit or mutilate textbooks," said David Torres, the agency's spokesman, insisting that all 1.5 million volumes of the textbooks would reach the students.

Asked how the agency would react if the Sonora governor kept his threat to issue re-edited versions of the text, Torres said: "He's not going to do it. He's going to abide by the law."

Reproductive rights groups, however, aren't leaving anything to chance.

They have sent a letter to dissenting governors, noting that Mexico's constitution prevents religious groups from interfering in education.

The separation of church and state has been inscribed in the constitution for 150 years in Mexico, where roughly 85 percent of the people are professed Roman Catholics. And while Mexicans may flock to see the pope, they often disregard his teachings.

A recent survey of 750 Mexico City residents found that 60 percent supported gay marriage, compared with 26 percent who were opposed. And 55 percent approved of premarital sex, according to the study in Mexico's El Universal newspaper.

"Ignoring what the priests tell us is part of the history of Mexico," said Maria de la Luz Estrada, an activist with the Mexico City-based group Catholics for the Right to Choose, which wrote the letter to the governors.

The letter notes that Mexico, which just ratified the U.N. Convention on the Rights of the Child, has committed itself to improve access to sex education for teenagers.

"This is not a matter for the governors to decide," Estrada said. "If they refuse to distribute the books, it's simple: They're breaking the law."