A burial mound in Tamil Nadu, India, holds the bodies of eight infant girls. Each of them was strangled at birth by their mother, who desperately wanted a son—so much so that she was willing to kill until she finally got one.

"Why keep girls when keeping them would be difficult?" the mother asks plainly.

Like a punch in the face, this is the opening scene of It's a Girl, a new documentary about a modern-day holocaust happening right under our noses. Shot on location in India and China by Shadowline Films, the hour-long film tells the stories of abandoned and trafficked girls, of brave mothers fighting to save their daughters' lives, and even of mothers who would kill for a son.

The United Nations estimates that as many as 200 million girls are missing in the world today because of "gendercide," the deliberate extermination of girls in favor of boys. It's a Girl, released last month, examines why girls are being annihilated at a rate that has skewed the sex ratio to biologically unsustainable levels in many parts of the world. Using a blend of hand-drawn animations and first-person interviews with mothers and fathers, doctors and demographers, activists and advocates for human rights, It's a Girl provides an excellent primer on the range and scope of gender injustice against girls.

Gendercide occurs most commonly through sex-selective abortion. Ultrasound technology has made it easy and cheap to determine the gender of an unborn child, thus ramping up the number of girls systematically exterminated before birth. Although India has laws against using ultrasound to discover the baby's sex, these laws do little to sway the deeply ingrained cultural bias for boys. Added to the centuries-old tradition of son preference are government mandates, like China's one-child policy, which has accelerated the elimination of girls.

Mark Shan, an analyst with Women's Rights Without Borders, describes in the film how the Chinese government boasts that the one-child policy has prevented more than 400 million births since it was instituted 32 years ago. That's 35,000 abortions a day—1,500 per hour—and many of these are forced abortions up to the ninth month, according to Reggie Littlejohn, president of the group Women's Rights Without Borders.

Evan Grae Davis didn't set out to make a film about gendercide. Originally the director and his production company were exploring the underlying roots of social injustices like gender inequality and the exploitation of the innocent. After researching human rights abuses across five continents, the team arrived in India, where they encountered a shocking reality.

"Nothing I had seen in my travels even remotely compared to the scale of routine injustice in the practice of gendercide," Davis says.

One such story from India is captured on film. Maya and Raju, an Indian couple, describe how their married daughter Latika was strangled by her husband when she failed to produce a son, a brutal form of domestic violence known as a "dowry death."

According to India's National Crimes Bureau, nearly 25,000 women are killed or maimed every year when their families fail to pay a dowry to the husband. Unfortunately, unless cases of families demanding dowry are reported, they are difficult to track. Plus, dowry abuse is no respecter of economic class. Parents of daughters lose assets relative to their wealth, so the rich and poor alike are victims of this illegal practice.

As bleak as these realities, It's a Girl is not a film without hope. It features several people and programs that are working to save the girl-child, such as Littlejohn's Women's Rights Without Frontiers, Rita Banerji, founder of 50 Million Missing Campaign, Sabu George, a public health activist in India, and Jing Zang, executive director of Women's Rights in China.

Davis's film released to a worldwide audience last month and is slated to screen at locations around the world, including at the European Parliament in Brussels and the British Parliament in London.

"Our heartfelt hope and desire is that … It's a Girl will capture hearts around the world and will compel us all to rise up and fuel a movement to end gender-based violence and killings and restore worth and dignity to the girls and women of India, China, and of the world."

To see the trailer and learn how to host a screening, go to ItsaGirlMovie.com.

Marian V. Liautaud is editor of Church Law and Tax resources for Christianity Today. Watch for her feature article on gendercide in the December 2012 issue of Christianity Today magazine.