Rodrigo Duterte at a news conference in May in Davao City, in the Philippines. (Jes Aznar/Getty Images)

The Philippines' tough-guy president-elect is turning his bare-knuckles campaign tactics on a potent adversary: the Roman Catholic Church and its opposition to artificial birth control.

Rodrigo Duterte, who takes office Thursday, is known for never mincing words or shying from a fight. He has threatened, presumably in jest, to chop off the penises of men who resist his proposals for wide-scale vasectomies, according to a report by the Associated Press on Monday. And he is on record as cursing the pope after a papal visit to the Philippines caused massive traffic jams in Manila.

But despite his famously vulgar utterances, Duterte appears to be dead serious about his crusade to lower the birthrate in his impoverished and fast-growing country of 102 million, where the majority-Catholic population has increased by 10 million in six years. The Philippines' birthrate of 2.9 children per family is much lower than in many African countries, where some average more than six children per family, but it is much higher than in Europe and in other Asian countries, including Japan and South Korea, which average 1.4 and 1.2 average births per family, respectively.

"I will reinstall the program of family planning. Three is enough," Duterte said Monday in a speech in Davao City, where he has governed as mayor or vice mayor for 22 years and where he instituted an ambitious policy of birth control and sterilization.

On Sunday, speaking on his weekly TV show from Davao, Duterte accused the church of keeping the public "in total ignorance" about birth control and frightening Catholics into submission. “You tell the children that they will go to hell. You always use that to scare them. But that is not true. Hell is here,” he told the audience, according to the website Politiko. Roman Catholic officials in the Philippines have opposed artificial birth control and advocate only natural family-planning methods.

Duterte, 69, earned the nickname "The Punisher" as a top official of the urban capital on Mindanao island, where criminals and troublemakers often turned up dead, at the hands of vigilante squads. But he was also credited with bringing peace and order to the violence-racked city, banning liquor sales at night and enacting other measures. A lawyer by profession, he also championed the cause of family planning during his long tenure, offering cash incentives to villagers willing to undergo sterilization. He won the presidential election in a landslide in May.

In his speech Monday, Duterte cited the efforts of former president Fidel Ramos, who promoted contraception use in the 1990s. Benigno Aquino III, the outgoing president, also fought with Catholic officials after enacting a law in 2012 that allowed the government to buy and distribute contraceptives at no cost. It also initiated sex-education programs in public schools.

But other political leaders have taken a strict conservative approach to the issue, despite the persistently high rates of birth. In 2000, the mayor of Manila instituted a 10-year ban on all contraceptive distribution in public city health centers, and U.S. aid programs ended family-planning services in 2008. Legal opposition to the contraceptive-distribution law persisted for many years until it was finally upheld by the country's Supreme Court. The Philippines also has one of the world's strictest laws against abortion.

The Catholic Church still opposes artificial birth-control methods, and after Pope Francis visited the Philippines early last year, he reaffirmed that stance on his return flight to Rome. Yet he also criticized families with too many children, urging people to use natural contraception methods. “Some think, excuse me if I use the word, that in order to be good Catholics, we have to be like rabbits — but no,” he said.

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