by Michael Zielenziger • June 1, 2009

When James Ross, the former chief operating officer of a Maryland-based engineering firm, hunts for new work at job fairs, he can’t help but notice a peculiar demographic fact.

“Nearly everyone out there is a man—and nearly everyone is about my age,” says Ross, 59, who lost his job in February. “In a room of 200 people, there may be 25 to 30 women.”

What Ross is seeing illustrates a striking—and labor experts say, unprecedented—transformation in the workforce that has shown up since the recession started in December 2007. Of the estimated 5.7 million Americans who have lost their jobs since then, 80 percent are men. And while unemployment for women over 55 rose from 2.9 percent in December 2007 to 5.4 percent in April 2009, according to the Bureau of Labor Statistics, the unemployment rate for men over 55 more than doubled in the same time period, from 3.3 percent in December 2007 to 6.7 percent in April.

Experts believe men are facing hardships because they are over-represented in the cyclical industries most affected by the downturn— manufacturing, construction, finance and engineering. The construction and manufacturing sectors alone have lost almost 2.5 million jobs. By contrast, female-dominated professions like nursing and education have been less hard hit.