Visualize a long line, more than 500,000 people long.

Look closer. They are all female. You’ll see lots of girls, some new born.

What you can’t see is the many who have had their genitalia mutilated. Those who haven’t are in danger.

This imaginary queue represents real people, the number of women and girls in the United States who were “at risk of or had been subjected to female genital mutilation/cutting (FGM/C) in 2012.”

The dispassionate language of a Government Accountability Office report reveals an alarming trend: the number of women and girls in the United States potentially facing or who have already suffered mutilation has grown threefold since 1990. A practice that should be extinct, now concerns many more people than the population of Atlanta.

Female genital mutilation generally isn’t considered a U.S. problem. But it is, primarily because of increased immigration from countries where it is practiced, rather than widespread cutting here.

Jaha Dukureh is one of the half-million. She was cut in Gambia when she was just one week old. Decades later, she is based in Atlanta where she founded Safe Hands for Girls to fight female genital mutilation. She still bears the scars, at least emotionally.

“It’s a part of my body that was taken away from me that’s never coming back,” she said by telephone. “Every woman wants to feel whole.”

Wherever the cutting is done, the 513,000 individuals in the Centers for Disease Control and Prevention (CDC) estimate now live in the United States. That means this country needs to do something about it. CDC’s estimate might be low. It does not take into account countries where female mutilation is practiced, but where there is no data. Nor does it include undocumented people.

“The CDC’s data aren’t perfect, but this estimate is very troubling and highlights how urgent it is that we do more to protect women and girls from this brutal form of gender-based violence,”  Senate Minority Leader Harry M. Reid (Nev.) told The Washington Post. “And it shows that more needs to be done to better understand the scope of this issue here in the United States.”

GAO’s report says female genital mutilation are “procedures that involve partial or total removal of the external female genitalia, or other harm to the female genitals for non-medical reasons.” Partially or totally cutting away the clitoris is an example. There are no health benefits, says the World Health Organization (WHO), only harm.

Female genital mutilation is rooted in the cultures of some African countries and elsewhere, including Indonesia, Colombia and India. Why is it done? Violent sexism is a big part of the answer.

“The purposes behind FGM are almost always based in patriarchy, but the reasons vary,” said Shelby Quast, director of Equality Now’s Americas office. Equality Now advocates women’s and girls’ rights internationally.

Among other factors, WHO says “FGM is often motivated by beliefs about what is considered acceptable sexual behavior. It aims to ensure premarital virginity and marital fidelity. FGM is in many communities believed to reduce a woman’s libido and therefore believed to help her resist extramarital sexual acts.”

Reid, who requested the GAO report, called the government’s lackluster response to female mutilation “truly shameful…many Americans haven’t even heard of FGM or they think it’s some far-away problem.  Although it’s illegal, it happens here, and we shouldn’t stand for it. The GAO reports lay out a number of actions our government can take to help address this terrible human rights violation.”

Specific federal laws against female genital mutilation have been on the books since 1996. Three years ago, Congress made it a crime to take a girl from the United States for the purpose of mutilating her abroad, a practice known as “vacation cutting.”

Yet, efforts by the mighty Uncle Sam against female genital mutilation are feeble.

Though genital mutilation is a crime and a violation of human rights, “law enforcement officials identified few investigations and prosecutions,” GAO reported. It found just two active programs aimed solely at female genital mutilation abroad, in Kenya and Guinea.

While multiple agencies have “ad hoc education and outreach efforts, it is unclear how these agencies will identify and implement needed efforts moving forward,” GAO said. “Absent a documented plan for each agency’s education and outreach efforts, the federal government may be unable to ensure that its activities to increase awareness” of female genital mutilation are effective.

Around the world, 6,000 females are cut every day, according to Dukureh. About 200 million are mutilation survivors.

“It’s not right,” she said, “to continue watching the girls suffer.”