A big reason America is falling behind other countries in science and math is that we have effectively written off a huge chunk of our population as uninterested in those fields or incapable of succeeding in them.

Women make up nearly half the work force but have just 26 percent of science, technology, engineering or math jobs, according to the Census Bureau. Blacks make up 11 percent of the workforce but just 6 percent of such jobs and Hispanics make up nearly 15 percent of the work force but hold 7 percent of those positions. There is no question that women and minorities have made progress in science and math in the last several decades, but their gains have been slow and halting. And in the fast-growing field of computer science, women’s representation has actually declined in the last 20 years, while minorities have made relatively small gains.

These jobs come with above-average pay and offer workers a wide choice of professions. Opening them to women and minorities would help reduce corrosive income inequality between whites and other groups, and would narrow the gender gap in wages. Improving the representation of women and minorities would also enrich American scientific research and development, because they will add a different perspective to workplaces currently dominated by white and Asian men.

Moreover, the people who do well in these professions will be much more likely to lead the industry in the future and make decisions that affect thousands of workers and customers. Many technology companies, including Twitter until recently, have no women on their board of directors, and few blacks and Hispanics in senior management roles, in part because too few girls and minorities are becoming programmers and engineers.

What’s Holding Them Back

The biggest career disadvantage faced by many lower-income blacks and Hispanics is their limited access to a good education. Compared with upper-income Americans, a greater percentage are raised by parents who have not gone to college or graduated from high school, and more grow up with single parents who do not have the time or resources to enrich their children’s education. Moreover, a smaller percentage of minority children attend enriching prekindergarten programs, which studies have shown aids the development of cognitive and analytical skills that are needed to do well in science and math. A recent study showed that nearly half of Hispanic 4-year-olds are not enrolled in any preschool classes. While more than 60 percent of black 4-year-olds are enrolled, most of them are in programs of low or mediocre quality.

Schools that serve minority and lower-income neighborhoods tend to employ teachers with fewer years of experience and less specialized training in math and science than schools in white and upper-income neighborhoods, according to a 2012 National Science Foundation report. By contrast, developed nations like Germany, South Korea and Belgium tend to devote more resources like teachers to schools that serve their most disadvantaged students than on schools that serve advantaged children, according to the Organization for Economic Cooperation and Development.

Lower Expectations

Entrenched stereotypes about who does well in science and math also work against minorities in classrooms. Too many teachers give up easily on them simply because they are not expected to do as well as white students. Despite those challenges, many minorities still enroll in science and math programs in college but fewer of them earn a degree in those programs in five years — 22.1 percent for Hispanics and 18.4 percent for blacks — than whites (33 percent) and Asians (42 percent), according to a study by researchers at the University of California, Los Angeles. Many of those who leave are simply ill-prepared for the rigors of college-level math and science. Others feel socially unwelcome because they make up a tiny minority in largely white and Asian science and engineering departments. They also have far fewer role models to look up to.

Unlike minority children, girls as a whole do about as well as or better than boys asmeasured by their high school grade point averages in science and math. And in the last several decades, women have made great gains in fields like biology, chemistry, psychology and sociology; they now earn a majority of undergraduate degrees and a growing proportion of advanced degrees in life sciences.

But women have made far fewer gains in physical sciences and more math-intensive fields. When making choices about their majors and careers, many young women rule out engineering and computer science partly because they are uninterested, feel ill-prepared for them or because society identifies these domains as male. Women who do earn degrees in these fields leave those professions at much higher rates than men. And the women who graduate with degrees in engineering and computer science are less likely to be employed than men.

In many cases, women seem to have internalized society’s belief that they are incapable of mastering these fields as well as men. Carol Dweck, a professor at Stanford, and other psychologists have found that female students who are made to believe that math ability is innate have lower scores and are less likely to study math than girls who believe that math skills can be acquired through hard work. Another study showed that female college students got more questions right on math tests when they were told beforehand that “college students are good at math” than when they were told “women are bad at math,” which suggests stereotypes undermine women’s performance.

Insufficient Resources

These gaps could be reduced if every child had access to free public preschools. Earlier this year, President Obama proposed making high-quality preschools available to 4-year-old children of families with incomes of up to 200 percent of the federal poverty line, at a 10-year cost of $75 billion. Studies have shown that every $1 invested in preschools saves society $7 in the future through lower spending on remedial education, higher productivity and less crime.

The country should also make sure that the schools that primarily serve minorities have the resources and support they need to hire qualified teachers so their students are not at a disadvantage relative to children in more affluent areas. States will need to take the lead to make this happen, but the federal government can also assist through grants and other support.

Conventional Teaching Methods

The Knowledge Is Power Program, which operates 141 public charter schools around the country, has effectively used smaller class sizes, longer school days and summer school to help lagging minority students improve test scores in math, reading and science. Teachers at KIPP schools maintain high expectations of all students, working intensively one-on-one with children until they comprehend every important concept. Though the program has been criticized for its dropout rates and admissions policies, one recent independentstudy of KIPP’s approach showed that middle school students who spent three years in its schools had math scores that on average put them 11 months ahead of where they would have been had they not joined the school; they were 14 months ahead in science achievement.

Teachers also need to make science and math education much more practical and hands-on. Girls have shown much more engagement in subjects when they learn the connectionbetween what they are studying and real-world problems. That may partly explain why so many talented girls prefer to go into life sciences, where that link has generally been more apparent.

Not Enough Role Models

Groups like the National Action Council for Minorities in Engineering have been showingminorities and girls that they can imagine themselves as scientists or engineers, providing role models to speak to middle school students and helping high schools set up engineering academies. A five-year program funded by the National Science Foundation at Bowie State University, a historically black university in Maryland, provides training and mentorship to high school science and math teachers and a summer science academy to 10th graders.

For both women and minorities, academic and social support is critical. The University of Maryland, Baltimore County has programs for minorities and women that provide students with scholarships, mentorship, internships and involvement in cutting-edge research. Students enrolled in its programs are much more likely to graduate than other comparable students.

More than half of the American population will be made up of minorities in 2043. And the number of women who are the primary or sole earner in their families is growing. Those trends make it imperative that one of the most dynamic sectors of our economy no longer remain a male and largely white and Asian domain.