Many college students who are initially drawn to math and science end up changing majors, reports Christopher Drew in a New York Times piece today. Why? In short, the classes are abstract, difficult and often large and impersonal, so it’s easy for those who are bored or struggling to fall between the cracks. Yet we know it’s a good idea to encourage students with any interest or aptitude at all in STEM (science, technology, engineering and math) fields to stick with them. Over the past decade, three times as many STEM jobs were created as non-STEM jobs, and STEM workers were less likely to be unemployed. Economists expect those trends to continue over the next ten years.

Perhaps the easiest way to get more Americans into STEM is to close the massive gender gaps in these fields. According to an August report from the Commerce Department, women hold just 25 percent of STEM positions. In rapidly expanding careers like computer science, the news is even worse: today, women hold 27 percent of all CS jobs, down from 30 percent a decade ago, and account for just 20 percent of undergraduate CS majors, down from 36 percent in 1986. The trend lines are going in the wrong direction.

Surveys of high-tech professionals find that most trace their interest in STEM back to their early childhoods. So what can parents and schools do to make sure girls become passionate about math, science, and technology? Here are some ideas backed up by research:

• Make sure your daughter has “tinkering” toys. Blocks, Knex, microscopes and model rocket kits will develop her spatial reasoning skills and encourage her to ask questions about the physical world.

• Allow her to play video and computer games, and even program her own! Lots of computer programmers get started as kids, developing tweaks and work-arounds to their favorite games. Free software like ALICE allows both kids and adults to learn the basics of computer-game programming at home. And if your daughter is exposed to programming at an early age, research shows she is less likely to drop-out of those challenging freshman-year introductory math, computing, and engineering courses, because she understands how the concepts can be applied in the real world.

• Ask your child’s teacher to make sure girls get equal time with classroom technology…even if boys push harder for computer time and girls seem less interested. Here are some great tips from a Virginia public school teacher.

Some of this advice goes against the grain of the trend toward technophobic parenting and schooling: the idea that children shouldn’t engage with computers, video games or iPads until they are 12 or 13. I happen to disagree, in part because we need to close gender, race and class disparities in access to technology and to high-tech jobs. All things in moderation.