A combination of strong forces, including baby boomer retirements and increased career options for women, is creating growing teacher shortages around the nation, says a Washington Post story. Some three quarters of the country's public school teachers are women, but research indicates that the number of women who pursue teaching after college, as well as their class rankings, has declined sharply since the 1960’s. “It’s not that you don’t have some terrifically talented people going into teaching," says Richard J. Murname, a Harvard economist who has studied the teaching profession. "The issue is you don’t have enough. And many are the most likely to leave teaching, because they have lots of other opportunities.” Compounding school recruiters' difficulties is the NCLB's highly qualified teacher mandate, which has tightened requirements for entering the profession.