But in July 1999 she was also a 44-year-old woman trying to get pregnant for the first time. And like so many middle-aged members of the military reserves, she wasn't wild about complying with an order to get six shots against anthrax, a deadly bacterium she doubted she'd ever have the misfortune to inhale. Savoie had heard that the shots, given over a two-month period, could have the type of side effects a pilot couldn't afford -- joint pain, vertigo, headaches. She worried they might interfere with her in vitro fertilization treatments -- or damage the child she hoped for.

And so, after 26 years in the Air Force and reserves, Maj. Savoie decided she was not going to get the shots. Her husband, Maj. James Hechtl, and more than half of the other 54 pilots in their reserve unit, the 301st Airlift Squadron at Travis Air Force Base in Northern California, avoided the shot as well, the couple says. Savoie was particularly outspoken in her opposition to the mandatory vaccine, attending hearings in Congress and talking to reporters.

"We've been accused of being disloyal and all kinds of things because we left over the vaccine," says Savoie. "Well, I'm sorry, but you can't use the military as a guinea pig anymore. We're much wiser, and with the Internet we're better informed."

The resignations at Travis Air Force Base are part of a pattern of resistance to the anthrax vaccine that has rippled across the country over the past two years. A quarter of all 176,000 pilots and other flight crew members in the Air Force Reserve and Air National Guard, which is also a reserve service, have either resigned or transferred out of their units in the past year, the General Accounting Office found in a study released Oct. 11. Another 18 percent said they planned to leave or transfer out in the next six months. In both cases, avoidance of the anthrax vaccine was by far the leading explanation the departing airmen gave GAO investigators, who sent questionnaires to a sample of 1,253 reservists. In a normal year, turnover of 10 to 15 percent might be expected. But if the GAO report is to be believed, mistrust of the military over the anthrax issue is high. Two-thirds of the respondents said the shot was a bad idea. And "despite DOD's (Department of Defense) high-visibility attempts to educate servicemembers about the anthrax inoculation program," the GAO report says, "only about 17 percent of those we surveyed believe the information on its Web site is accurate."

The anthrax protection program has been marked by controversy since the Pentagon, in May 1998, announced it would inoculate all 2.4 million servicemembers, active and reserve, in the first step of a multibillion-dollar biowarfare defense program. So far, fewer than 500,000 have received the anthrax vaccination, and the military, much to its embarrassment, was forced to suspend most vaccinations on July 17 because its stocks had gotten low. The only factory that makes anthrax vaccine has been closed for several years and has yet to win Food and Drug Administration approval to start making the shots again.

Reservists, who can opt out of military jobs easier than active-duty troops, have put up the most resistance to the vaccine. Pilots appear to have been particularly leery because they have to be in tiptop shape to fly. At some bases, including Travis, airmen transferred to other assignments in hopes that they could stay one step ahead of the vaccination campaign without being forced to refuse a direct order.

Reps. Dan Burton, R-Ind., and Chris Shays, R-Conn., have spearheaded a two-year investigation of the anthrax vaccination program as members of the Government Reform Committee. They ordered the GAO study, saying the vaccine campaign is misguided and seriously undermining the nation's military readiness, a sentiment shared by some pilots. Politics plays a role here, but even Democrats on the committee, and staunch advocates of the health bureaucracy such as Rep. Connie Morella, R-Md., have joined in questioning the value of the campaign.

Guard and reserve units are an increasingly key part of America's all-volunteer military. These weekend warriors have been at the front lines of all the major U.S. military operations of the past decade, from the Mideast to Rwanda to Kosovo.

The anthrax vaccination program is the lead element of a strategic shift in U.S. doctrine, moving away from the threat of mass retaliation as a deterrent to biowarfare attacks and instead embracing the goal of providing immunological protection for individual soldiers. That makes the reservists' skepticism of the program all the more serious. An estimated 65 officers and enlisted men have been court-martialed for refusing the shots, and hundreds of others have allegedly been threatened or punished in less serious ways.