A gender gap exists in most American schools, with girls leading academically in most subjects and boys falling behind. Educators seeking ways to narrow or eliminate the gap should consider single-sex classrooms.

National and state assessments indicate the scope of the problem:

• Writing: In 2007, 49 percent of fifth-grade Pennsylvania boys were proficient writers compared to 66 percent of girls. Even in 11th grade the gap remains, with 84 percent of boys and 92 percent of girls scoring at the proficient level.

• Reading: In 2007, girls outscored boys in grades 3-8. In 11th grade only 61 percent of boys scored as proficient compared to 70 percent of girls.

• Science: Nationally, boys in the fourth, eighth and 12th grades have consistently outscored girls in science since 1996.

Why do boys lag in reading and writing subjects? Why do girls lag in science? Are the stereotypes true -- girls are just naturally better readers and writers, and boys just do better in science? Are boys and girls steered by adults in different directions? Or do boys and girls learn differently?

Anyone who watches a preschool classroom can see gender differences. In general, little girls are more social and likely to work in groups. Boys are louder and more active and will play with whomever wants to share the toys. These observations are not "sexist." They are what educators and parents see everyday.

Medical technology, such as MRI and PET scans, has opened up the world of biological differences between boys and girls. A 2007 study by the National Institutes of Health found that different regions of the brain develop in a different sequence in girls and boys. This confirms earlier findings that girls' brains mature six years earlier than boys in language and fine motor skills while boys are four years ahead in spatial memory. The genders differ in hearing and vision also. Girls hear two to four times better than boys. Anatomical differences in the eye enable girls to discern details and boys to follow the action. Dr. Leonard Sax's book, "Why Gender Matters," explains these findings and much more.

What does all this mean? Boys and girls grow and learn differently. One is not better than the other -- they are just inherently different.

This understanding has profound implications for the classroom. When a soft-voiced kindergarten teacher tells the children to sit down and the little girls comply while the boys continue to play, it is often assumed that the boys are misbehaving or exhibiting symptoms of attention deficit hyperactivity disorder. Instead, the boys simply may not have heard the teacher. When working on projects, girls may work best sitting together and discussing ideas, and boys may need to move around and challenge each other's ideas. They are all learning -- just differently.

Since scientific findings and classroom observations confirm that boys and girls learn differently, it seems logical for educators to adapt classroom practices to meet the needs of both. A recent Stetson University study supports this idea.

Public elementary school students in Florida were placed in coed or single-sex classes. The findings after three years are clear: Both boys and girls in the single-sex classes increased their academic performance more than those in the mixed classes. The researchers concluded that single-gender classes are a viable education option.

Dr. Sax asserts that single-sex classrooms are successful because they break down gender stereotypes. "Girls in single-sex educational settings are more likely to take classes in math, science and information technology. Boys in single-sex schools are more likely to pursue interests in art, music, drama and foreign languages."

Boys and girls can learn the same curriculum more successfully when educators are taught to use gender-appropriate teaching strategies. Boys and girls both win!

About 30 years ago educators decided that girls were being underserved in education. Special programs were started and curricula were revised, especially in math. Math scores from the Pennsylvania System of School Assessment show some of the results. while math is traditionally a male-dominated subject, boys and girls in Pennsylvania now score about the same in all grades.

A recent movement to improve science education for girls, such as the Carnegie Science Center's Girls, Math & Science Partnership, may ultimately succeed in preparing more girls to study engineering. The National Science Foundation reports that in 2004, more than 51,000 males attained undergraduate engineering degrees, compared to only 13,000 females. If female-focused programs help girls to learn math and science better, then male-centered reading and writing programs may help boys. Neither gender is hurt when both are given the opportunity to learn and excel.

A practical aspect of single-sex education that should not be overlooked is the cost. For schools that have enough students in a grade to offer single-sex and coed classes, implementation is cost-neutral. The same curriculum is used and additional teacher training can be provided through required professional development programs.

Teachers in several coed Pittsburgh-area schools are to be applauded for recognizing gender differences and piloting single-sex classrooms. They are joining almost 350 public schools across the country that offer single-sex educational programs so that both boys and girls have the opportunity to reach their full potential.