This is likely to be the new civil rights challenge, and it affects mostly boys. From the New York Times:
Raising new questions about the effectiveness of school discipline, a report scheduled for release on Tuesday found that 31 percent of Texas students were suspended off campus or expelled at least once during their years in middle and high school -- at an average of almost four times apiece. When also considering less serious infractions punished by in-school suspensions, the rate climbed to nearly 60 percent, according to the study by the Council of State Governments, with one in seven students facing such disciplinary measures at least 11 times. The study linked these disciplinary actions to lower rates of graduation and higher rates of later criminal activity and found that minority students were more likely than whites to face the more severe punishments. "In the last 20 to 25 years, there have been dramatic increases in the number of suspensions and expulsions," said Michael Thompson, who headed the study as director of the Justice Center at the Council of State Governments, a nonpartisan group. "This quantifies how you're in the minority if you have not been removed from the classroom at least once. This is not just being sent to the principal's office, and it's not after-school detention or weekend detention or extra homework. This is in the student's record."