Whether you're looking for a job, or looking to hire – computer expertise is the most in-demand skill in the American job market.

The computing industry's rate of job growth is three times the U.S. national average, according to statistics, and yet women are being left behind.

Only one in five professional computing occupations are held by women. In 2016, just 19 percent of women graduated with a Computer and Information Science degree. However, women made up 57 percent of bachelor degree recipients.

So why are women falling behind in the tech sector?

"We need to create new pathways for women into technology. That first opening computer science class at college is too late," Melinda Gates, of the Bill and Melinda Gates Foundation told CNBC in an interview.

That's why organizations like Girls Who Code start teaching girls as young as third grade about coding.

"We have to start as young as we possibly can because we know that essentially it's in middle school where all of a sudden these subjects aren't cool," Reshma Saujani, Girls Who Code Founder & CEO, told CNBC's "On the Money."

The non-profit launched in 2012, and offers programs that are free for girls. Funding comes from a mix of individual and corporate contributions.

"We run free summer programs for rising juniors and seniors in high school, and we run them at about 80 different technology companies from Facebook to Twitter to Adobe to Prudential to Microsoft to Sephora. And then we run free after school clubs." Saujani told CNBC.

The founder said there are about 4,000 Girls Who Code clubs in all 50 states. According to the organization, the program has 90,000 alumni, and 5,000 of the young women are college-aged. The alumni who have declared majors are choosing computer science, or a related field, at rates 15 times the national average.

Saujani, who is not a coder herself, started this organization after a career in corporate law and failed bids for public office.

"I'm a weird person to have started this organization. I was terrified of math and science growing up. I wasn't a coder," she told CNBC. "I was running for office and I would go into schools and see dozens of boys clamoring to be the next Steve Jobs or Mark Zuckerberg, and I thought 'where are the girls?'"

She added: "My parents came here as refugees, I've had a job since I was 12, and I knew having a great education, having the opportunity to march up into the middle class had changed my life and my family's life. And I knew that technology jobs were our future of work. I wanted to make sure that every girl in America had that opportunity."

Over the past six years, Saujani explained that she's gained insight into why more girls and young women don't pursue computer science, and it's because they don't see it around them.

"You're listening to culture, you're wearing the t-shirt that says 'I'm allergic to algebra,' you're watching "Mean Girls" on repeat, and you're getting all these messages that math and science are not for you, and you start listening and that's where we need to intervene," Saujani added.

"I always say that I stalk Shonda Rhimes like it's my job," she joked, referring to the creator of hit television series like "Grey's Anatomy" and "Scandal." Saujani said that the idea was to " create the next television show about the next girl coder, because culture is everything."

The founder says she's also learned that girls should be brave, but not perfect.

"From the time girls are young, we are teaching them to smile and be pretty, to play it safe and get all A's," she said. "And we're not teaching them to take risk, we're not teaching them to fail. And so much about coding is about failing."

On the Money airs on CNBC Saturdays at 5:30 am ET, or check listings for air times in local markets.

