Ralph, a 38-year-old film director, tries to explain his problem. "Until my mid-twenties, I always thought: 'Okay, I'll get to grips with this somehow.'" He was 25 when he first downloaded child pornography from the Internet.

Right from the start, he knew that his actions weren't right. "But it's hard to implement that," he says, "because it's always a feeling that's inside me, a completely normal feeling of love or comfort, of affection for someone."

Ralph didn't know what to do. But after asking a girl online to send him more pictures, he slammed on the brakes and contacted the German prevention network for pedophiles: "Don't Offend" ("Kein Täter werden"). He told his story on the network's website - as a warning to people who feel turned on by children.

People with pedophilic inclinations are sexually attracted to children. Sex therapists report that it is usually men, rather than women, who have such sexual fantasies. Some desire girls, some boys. Many are driven by their desires to search for material online.

There is an enormous amount of child pornography on the Internet. In Operation Spade in October 2013 alone, the Canadian police seized enough pornographic material for 33,000 feature-length films. The arrest of the leaders of this pornography ring dealt a significant blow to the child porn industry.

Pedophilic pictures are not so black-and-white

According to German law, the possession or dissemination of child pornography is a criminal act. Sexual acts with children, by children or in front of children are also illegal. But the boundaries aren't as clear as it would seem. For example, can a picture of a naked child playing on the beach be considered pornographic?

The police uses the so-called COPINE scale as a guideline in child pornography investigations. It helps to determine how problematic the images are. The scale starts with pictures of children in fashion catalogues. "Then the levels sort of escalate," explains criminal law expert Arnd Hüneke from Hanover. Everything from level seven, where sexual activities are shown, is illegal; but in between there is a gray area, which covers photos or films of naked children determined to be "posing."

Don't offend

How closely is the consumption of child pornography really connected to actual child abuse? As Petya Schuhmann, a psychologist from the sexual research out-patient clinic at Regensburg University explains, "Not everyone who looks at child pornography acts on that desire."

Schuhmann explains that it is still unclear whether or not there is a connection. What is clear, however, is that children who are made to show their genitals for images or films, or who are forced into participating in sexual acts, are victims of abuse. They have to be protected by the law, but also with the help of projects like "Don't Offend." Since 2005, this prevention project has been offering therapy for pedophiles across Germany.

The people who come to Petya Schuhmann's Regensburg sexual research clinic are usually suffering from severe psychological stress. "A pedophilic inclination isn't something that you choose yourself, or that you can just turn off," says Schuhmann.

The therapist explains that the sexual fantasies of those who come looking for help are putting them under real strain. For many, their visit to the center is the first time they have confided in anyone. Pedophilia is normally equated with child abuse - and the shame that goes along with it runs deep, even when desires haven't actually led to actions.

Learning empathy for victims

In the diagnosis, the question of whether a pedophile is "only" consuming nude photographs or heavier pornographic material is irrelevant. Instead, a more precise sexual history is necessary: What type of sexual fantasies is a man projecting onto children? What are the potentially dangerous scenarios for pedophiles? How much pornography is being consumed? Some patients have already crossed the line into abuse but their actions have gone undetected by law enforcement. Most, however, are simply afraid that they might abuse a child.

The goals of the therapy provided by "Don't Offend" include stopping any sexual contact with children, stopping pedophiles' consumption of child pornography, and helping pedophiles to learn to live with their sexual inclinations. Patients meet every week for group therapy. The treatment they undergo aims to change their behavior.

All the potentially dangerous scenarios are played out. How do I act with young nieces at family parties? How do I behave near a playground - or at home alone at my computer? Child pornography is completely taboo, but many patients go a step further and refuse to look at any material at all that has children in it. "Then it doesn't matter anymore then whether it's nude pictures of children at the beach, or legal 'posing' pictures," says Schuhmann.

Many of her patients are afraid they will commit criminal acts. "They don't want any children to be harmed, either," says Petya Schuhmann. That is a goal of the therapy as well: developing the patients' empathy with the victims. When their empathy increases, they become more aware of how traumatic the pornographic representations can be for the abused children.

Therapy has helped Ralph learn to deal with his pedophilic inclinations. "I was repressing the fact that children are being abused in order to produce the photos," he writes on the homepage of the "Don't Offend" network. Thanks to the therapy, he was able to tell his parents everything.

He will probably never be able to be completely normal around children. But he is able to protect himself from his urges - and thereby protect children from potential abuse.