Kids in wheelchairs, kids who can't talk, kids who can't read -- increasingly students with disabilities are being taught in the regular classroom alongside their non-disabled peers. The practice, known as inclusion, emerged in the early 1990s and is spreading. In Arlington and Howard counties, school boards now actively promote it. Other suburban districts permit inclusion in individual schools, while the District of Columbia still relies on separate special-education classes for the disabled. Nationwide, the trend toward inclusion is growing: According to the Department of Education, in 1991 fewer than 33 percent of the country's disabled students spent most of their day in regular classes; four years later that percentage had reached 44 percent. Inclusion is the latest stage in a swift overhaul of America's approach to special education. As late as the 1970s, millions of children with disabilities were institutionalized and unschooled. Spurred by lawsuits and a growing recognition of the rights of the handicapped, Congress in 1975 enacted what is now known as the Individuals With Disabilities Education Act. This landmark legislation, extensively revised last year, requires that schools teach disabled youth in the "least restrictive environment" and provides funds to states to help them do it. Inclusion goes one step beyond the '80s practice of mainstreaming, which involved moving disabled students out of special education into regular classes when they were deemed ready. Inclusion presumes that from day one, schools should try to teach disabled children in the regular classroom. Educators say that if done properly, inclusion usually works. The majority of students classified as disabled have learning disabilities that make it hard for them to read and write, emotional disorders, speech problems or mental retardation. In most cases, they need extra attention from specially trained assistants who accompany them in the classroom. Inclusive teaching methods emphasize teacher collaboration, behavior modification and children working in small groups on individual and collective study goals. Inclusion's advocates believe that even ordinary school tasks, such as dribbling a basketball or drawing story characters, can help disabled students improve motor, cognitive and social skills. The result? A 1993 study by the Department of Education found disabled students taught in inclusive classes were more likely to hold jobs and participate in their communities after high school. Inclusion is not always done properly, however. Some schools have dumped kids into classrooms without extra teaching assistants or more training for teachers. Studies show that disabled children shuffled into regular classes without support are more likely to drop out of high school. Inclusion places new demands on teachers, especially "if a child cannot perform the tasks at all," says Mark Glaser, a learning disabilities teacher at Edison High School in Fairfax County. A disruptive child may also interfere with the rest of the class. And while inclusion may benefit a majority of disabled children, it doesn't seem to help all of them -- as many as 20 to 30 percent of disabled students in even the best inclusive classrooms don't improve academically, says Vanderbilt University researcher Douglas Fuchs. Educators are currently debating whether separate classes and facilities for the disabled could be abolished entirely. But some teachers, parents and advocates, such as the Learning Disabilities Association of America, maintain that certain kids simply will not thrive in a regular classroom. How does inclusion affect non-disabled students? When implemented correctly, says Thomas Hehir, the Department of Education's director of special education programs, it "has a positive impact on the classroom, not a negative impact." Diane Tessier-Switlick, assistant principal at Gaithersburg Middle School and co-author of a textbook on inclusion, says that presenting lesson material in different ways, so as to reach disabled students, reinforces learning for non-disabled kids. Cherie Takemoto credits inclusion at McKinley Elementary School in Arlington with helping reshape her learning-disabled son's future. Once she believed he would always be dependent; today she foresees "a self-sufficient young man who is not going to need a group home or supported work environment." Susan DeFord is a freelance writer living in Silver Spring.