According to the U.S. National Science Foundation, only 11 per cent of practicing engineers in American are women. In Canada, a 2009 study found women make up only 10 per cent of all professional engineers.
Debbie Sterling, a Stanford engineer based in San Francisco, thinks one reason girls don't really go into engineering is that they're not even aware of it. She says she didn't discover it until she was a senior in high school.
After studying the issue for a year, Sterling decided that toys are a big part of the equation: boys tend to play with Lego, Kinex and Erector sets, all of which "develop spacial skills and get kids interested in engineering and science."
The aisles where girls' toys are sold are filled with dolls and princess dresses.
And while boys are often fired up by building things, Sterling read various psychological studies that found many girls prefer reading.
Sterling decided the best way to get girls into engineering early on was to combine that love of reading with a toy set that encourages spacial awareness.
"It all came down to one simple thing: boys like building and girls like reading," she said. "So I thought, what if I put those two things together, spatial plus verbal, book series plus building set."
In order to accomplish her goal, Sterling started a company called GoldieBlox to manufacture a new toy set containing a building kit and a story book. Here's her original, home-made prototype:
The main character is Goldie, a princess who likes to build. As they read along, girls build objects to solve problems that Goldie faces.
"It appeals to girls because they aren't just interested in 'what' they're building, they want to know 'why', " says Sterling. "Goldie's stories relate to girls' lives - the machines she builds solve problems and help her friends."
She tested her prototype with more than 100 kids, and created a Kickstarter page with a goal to raise $150,000 to manufacture the first 5,000 GoldieBlox sets. In the end, Sterling almost doubled her target: in total, she raised $285,881.
The first sets are due to ship in April 2013.
Toys may be part of the equation, but why else don't more women get into engineering?
There are a lot of theories: Dr. Tyseer Aboulnasr, dean of applied science at the University of BC, puts some blame on engineers themselves.
"Collectively, we have focused too much on the technology side, on building things," she told the Globe and Mail.
Dr. Aboulnasr believe women tend to want to help people and get into careers where they can make a meaningful contribution to society.
"Somehow we have lost the message that engineering can improve people's lives," she said.
Another reason some women may not enjoy engineering is the male-dominated environment, which can lead to discriminatory behaviour.
"It's still a difficult place for women to be," says Kerry Black, a former master's student in civil engineering at UBC. When she was doing her undergrad, she says she faced discrimination: "I like makeup, I like to dress up and wear high heels and that made me a target. There were comments made in the classroom and that did bother me."
For Black, connecting with a female mentor, one of her professors, was the key to remaining in the engineering field.
In 2011, Engineers Canada created the Women in Engineering Committee, with representatives from various industry and academic groups. Their goal is to attract and retain more women, and achieve equity and diversity in the profession.