ISIS is repeatedly committing a heinous crime on humanity, one that is spoken about markedly less often than the group’s other acts of terrorism that make headlines.

Sex slavery is a growing epidemic in the Islamic State. According to Dr. Jonathan Kuiken, assistant professor of global history and languages, sex slavery is permitted by the religious law of ISIS.

While raping sex slaves is permitted by ISIS law, women who are pregnant and Muslim women are not permitted to be sex slaves.

“A lot of these laws that ISIS is calling on to justify what they’re doing were actually laws sometimes from the preaching of the Prophet Mohammed himself, sometimes from these early years of Islam,” Kuiken explained.

The early years, according to Kuiken, were the first 70 or 80 years. He went on to explain that these laws were written in the 7th century, when the usual practice of a marauding army was to rape and pillage.

The laws were meant to allow rape and pillaging, with the moral limitation of never injuring a child and never raping Muslim women.

“Of course as society evolves in the Middle East and elsewhere, we kind of move away from this idea that you have a right to rape and pillage.

“So in some kind of odd way, ISIS is taking these laws, that were actually somewhat progressive in the 7th century, and applying them in the 21st century in really retrograde ways,” Kuiken said.

Women of Yazidi origin in regions that ISIS overtook were highly prized because they fell into the slim category that allowed them to be taken as slaves by the ISIS law.

Thus, they could promise foreign fighters that if they fought for ISIS, they would receive sex slaves among all of the other things promised, such as housing and money, Kuiken said.

However, if these women were to become pregnant, they would not be able to be used in the sex trade.

“So there have been reports that they are forcing these sexual slaves to take contraceptives so that they don’t get pregnant, and it shows in some ways that these women are actually a very important part of the ISIS economy,” Kuiken said.

Kuiken reluctantly described the scenario in black and white terms, saying that there is a large demand for these slaves, with a very limited supply because of the limitations on who can be used as a sex slave.

“Supposedly, these women get passed from fighter to fighter; as the fighter gets killed in battle or blows himself up, his sex slave gets passed to the next foreign fighter,” Kuiken said.

“So if they get pregnant, ISIS loses that ability to use them as a bargaining chip, as a form of payment. It’s kind of a very perverse logic, but a logic nonetheless.”

Kuiken maintains that ISIS law is quite different from Islamic law.

“They [ISIS] pick and chose their history… in theory, what they claim to want is to return to this time of really early Islamic history… It makes it very convenient because you can pick little bits and pieces to construct the world that you want.

“It’s kind of a gross misuse of history and theology in order to kind of do what they want to do… it is a deeply developed school of thought, I mean many of them are very smart, but most Islamic scholars, I think, would point out that they are misusing some of this historical precedent or twisting it,” Kuiken explained.

“A smart bad guy never just makes stuff up. They always take something that is legitimate and twist it to meet their own ends. So basically, everything that ISIS teaches and preaches does have some tie to actual Islamic history or teaching, but not in a way that most scholars would recognize as valid or legitimate.”