When teachers returning to middle school in Turkey opened the new edition of a textbook on biological reproduction, they found that illustrations of human genitalia had been replaced with images of ducklings, bears, and other cute animals.

The censoring, which included striking words from the text such as "breast," is the latest in a series of moves by Turkish President Recep Tayyip Erdogan and his Justice and Development Party (AKP) to promote Sunni Islam and conservative values in schools.

Although Mustafa Kemal Ataturk, Turkey's first president, abolished the Ottoman Caliphate and declared a democratic republic as well as broad reforms secularizing education and subjugating Islam to the new modern state, religion remained a strong undercurrent in Turkish society. Erdogan deftly consolidated power and championed political Islam when he took office as prime minister in 2003.

After presiding over the government for 11 years, he became the country's first popularly elected president in August — and has made little secret of his intention to strengthen the historically ceremonial post and maintain authority. Although a recent Pew Research survey found that Erdogan's approval rating had dipped 15 points since 2007, almost two-thirds of conservative Muslims still support him, and he was overwhelmingly favored in the election.

'If you remove compulsory religious culture and morality classes, then naturally drugs will fill the vacuum; violence and racism will fill the vacuum.'

The textbook adjustment is hardly the first time officials have taken dramatic action to, in their view, protect students and conservative values. In 2012, the minister of defense brought charges against nine officers for screening Game of Thrones while teaching English to military cadets.

The prohibition was recently codified, according to a report in Hurriyet Daily News, with the Turkish army formally banning such shows for their display of "sexual exploitation, pornography, exhibitionism, abuse, harassment and all negative behaviors." According to another regulation, the traditionally secularist military must also offer cadets elective religious courses on Islam.

Altering curriculum is a significant political issue, according to Burcu Yilmaz, an education expert at the Egitim Sen teacher's union, a left-leaning group that opposes religious class requirements. Replacing human reproductive organs with adorable animals in a textbook, for example, requires the full government cabinet to meet.

Yilmaz told VICE News that the AKP aims to "force religion on students" and cleanse the curriculum of any theories, like Darwinism, that challenge Islamic precepts. She noted that the government revised high school philosophy coursework just last year, removing Western thinkers like Karl Marx and emphasizing Sunni Islamic thought.

Turkish students typically spend over 1000 hours on religion before entering high school, according to Egitim Sen, compared to less than 800 hours on math.

Although 99 percent of Turks are officially Islamic, many Muslims are uncomfortable with the role of religion in schools. Despite the predominance of Sunni Islam, between 5 and 12 percent of the Turkish population is Alevi, a belief system that draws from both Shia and Sunni Islam as well as other traditions.

A group of Alevi families recently won a landmark ruling against the Turkish government at the European Court of Human Rights (ECHR). The court found that Turkey's compulsory religion courses promote Sunni Islam and are a violation of the "right to education" stipulated in the European Convention on Human Rights, which the nation has signed.

The ECHR called on Turkey to "remedy the situation without delay, in particular by introducing a system whereby pupils could be exempted from religion and ethics classes without their parents having to disclose their own religious or philosophical convictions."

Erdogan dismissed the ruling.

"You cannot see anywhere in the world that compulsory courses on mathematics, physics, or chemistry are being made a matter debate. But for some reason, classes on religious culture and morality are always a matter of debate," he said. "If you remove compulsory religious culture and morality classes, then naturally drugs will fill the vacuum; violence and racism will fill the vacuum."

Alevis and families of other faiths were outraged this year when 40,000 students were assigned to vocational training schools for imams, often against their will, as part of a 2012 government reform measure. These schools, called imam hatips, have long been a flashpoint of debate between secularists and Islamists in Turkey. In 1997 the Turkish military forced an Islamist prime minister from office and then shut all imam hatip middle schools. Protests fought against the passage of the reform legislation in 2012, arguing that it would vastly expand the influence and reach of such schools.

Erdogan, an iman hatip graduate, has since reopened religious middle schools in force. A report by Education Reform Initiative (ERI), a non-governmental think tank, indicates that the Turkish government has been feverishly converting public schools into vocational religious schools — the number of which has increased by 73 percent over the past four years. Enrollment is back up to 10 percent, the same level as before 1997.

Batuhan Aydagul, ERI coordinator, told VICE News that students at these schools are required to spend a third of their time studying Sunni Islam, and girls must wear the veil when they read the Qur'an.

'We should not plan them [the schools] as mixed-sex. We should not think about regular high schools any more.'

Outraged by the increasing role of Sunni Islam in education, in October leaders from the Alevi community marched for seven days from northern Turkey to Ankara. Thousands gathered under a red sea of Turkish flags and a 20-foot banner of the Prophet Ali — whom Alevis revere alongside Allah and Muhammad — relentlessly chanting, "With 100,000 imams and mandatory religion, the state can't be secular!"

For many Alevi, the influence of Sunni Islam in schools is "becoming part of a victimization narrative," Ayse Ezgi Gurcan, a political scientist and fellow at the Istanbul Policy Center, told VICE News. The effect, she said, makes them feel as though the government is out to get them.

Erdogan has long advocated for the expression of Islam in education. When the AKP attempted to lift the ban on women's headscarves in universities in 2008, the constitutional court sanctioned the party for anti-secularism. Erdogan gained control over the judicial branch by 2010, and lifted the ban.

In September, his cabinet amended the regulation on student dress, forbidding tattoos, body piercings, and the use of makeup while allowing girls as young as ten to wear the veil in public school.

Aydagul thinks that the political struggle over education has neglected teachers, and believes that quality won't improve without policies that drive achievement. ERI's report shows that high school reading and math scores have flatlined since 2008.

At Egitim Sen, Yilmaz worries that the AKP now has its sights on ending coeducation. She said that in two different incidents last year, pro-AKP school directors forced girls and boys to sit separately in schools. In September, members of the Egitim Bir-Sen, a conservative teacher's union, declared that the imposition of coeducation violates personal preference.

"Following the signature campaign and organizing acts of civil disobedience in previous years, the ban on the headscarf was removed," they said. "Now we will pursue civil disobedience until other prohibitions and obligations such as wearing a tie, teachers with beards, and coeducation come to a halt."

Earlier this year, an opposing political party claimed that one of Erdogan's sons, Bilal, had been recorded urging the conversion of high schools into imam hatips and outlining the end of mixed sexes in meetings about education policy.

"We should plan the schools in future by sex," Bilal allegedly remarks on the tape presented to Turkish media. "Currently, there are mixed-sex schools. We should turn them into secondary or high schools by sex. I mean, we should not plan them [the schools] as mixed-sex. We should not think about regular high schools any more."

As rapid as the recent changes have been, if the AKP wins a two-thirds majority in the June 2015 parliamentary elections and clinches Erdogan's control over all three branches of government, the pace of reform could very well quicken.