Statistics show that the majority of current members of the military are the children of current or former servicemembers. After 40 years of an all-volunteer military, this has many government and military leaders worried that Americans are growing detached from the sacrifices of war.

WASHINGTON — Before a roadside bomb in Baghdad burned and tore apart Jerry Majetich, before 62 operations put him back together, even before he volunteered for the Marines, then the Army, there were five older brothers who’d enlisted and a mother who’d served as an Army nurse in Korea.

His family background shaped former Staff Sgt. Majetich, who’s now 42, a single father and an investment firm vice president in Jacksonville, Fla. Despite the torment since the 2005 blast, that history is part of what moved his 21-year-old son to consider leaving college to pursue a military career, and his 17-year-old daughter to join her high school Reserve Officers’ Training Corps.

“I’d be thrilled if they chose to serve,” he said. “Despite everything, I believe in military service.”

This month marks 40 years since the United States ended the military draft, and an ever smaller slice of the population appears to share Majetich’s belief. Statistics are rare, but a Department of Defense 2011 Status of Forces survey indicated that 57 percent of active troops today are the children of current or former active or reserve members of the armed forces.

A recent Gallup poll showed that despite the wars in Iraq and Afghanistan, a much smaller percentage of those who’ve reached military age since Sept. 11, 2001, have served than in previous decades.

Part of it is simple demographics. While the U.S. population has grown since the draft ended in 1973, the military has shrunk. But this all-volunteer force appears to be passing from generation to generation, bringing up the worrying notion that the United States is developing a warrior class.

“The declining veteran population is one of our concerns, since there are fewer young adults in American society who are exposed to military service,” said Lt. Cmdr. Nate Christensen, a Pentagon spokesman. “While the armed forces continue to be largely representative of the country as a whole, nearly four decades of an all-volunteer force has shaped who is most likely to serve and from where.”

In the wide halls of the Pentagon, the military often is referred to as “the world’s largest family business.” The fear among some military leaders, politicians and experts begins with the belief that as fewer segments of society have family or friends in uniform, others become desensitized to the risks and stresses of military service. The feared risks range from a reluctance to fully support those who serve to an almost cavalier willingness to wage war, reasoning, “That’s what THEY signed up for.”

Historically, problems with such classes have ranged from the military having too much influence in all walks of society — Prussian officers collected taxes — to being marginalized, as with the so-called “barbarization” of the Roman military, which relied heavily on non-Romans.

Sen. James Inhofe, R-Okla., has spent decades voicing such fears. He’s one of the few politicians around who still yearn for a draft.

“Now, we’re never going to get the draft back,” he said. “But I really believe the greatest risk isn’t to the military and the few who serve, it’s to the rest of society.”

Inhofe thinks that military service makes better citizens. The broader the base of volunteers, he said, the better.

Even in a conservative state such as Oklahoma, Tulsa residents — more distant from military bases than other parts of the state are — express less interest in Afghanistan and other defense issues than those who interact more often with the military, he said.

“It’s only natural that people are becoming more and more distant from the military,” Inhofe said. “It’s a nationwide trend.”

The concept of a warrior class isn’t new, nor is it unique to the United States. Japan had its samurai. Europe had knights and vassals. The Aztecs had warrior nobility known as the Shorn Ones.

Israel, with nearly 8 million people, avoids this by having everyone serve. That wouldn’t work in the U.S., with a population of 310 million and a military of 1.5 million. Military leaders widely prefer a volunteer force, and one that’s committed to learning and staying on the job, to a conscripted one that can’t wait to muster out.

Still, Michael O’Hanlon, a defense policy expert at the Brookings Institution, a research center based in Washington, worries that whole segments of the population won’t even consider military service in the coming decades. When that happens, do those serving lose political clout?

“A broader base of volunteers helps ensure we don’t stop paying attention,” he said.

The military relies heavily on volunteers from the South and Midwest. Current trends might lead to an even narrower pool of volunteers.

Military and civilian officials admit that there are some positives in the smaller recruiting pool. The children of service members enlist understanding the job. They often were raised around the military and aren’t shocked by the culture, the level of expectations or long deployments.

Consider the Cotter brothers, who share a military life in the Flint Hills of central Kansas.

Several years ago, with college over and the recession in full swing, Gregory Cotter realized that his teenage dream of escaping the family business was a mistake.

“As a teenager, I wanted to do anything but this,” he said

But like his father and two brothers, he enrolled in the Army. A tour in Afghanistan now behind him, Sgt. Cotter, 27, lives at Fort Riley, along with his twin, Andrew, a lieutenant, and their 28-year-old brother, Brian, a captain, both of whom served in Iraq. Their father, Col. David Cotter, retired not too far away, in Platte City, Mo., outside Kansas City.

“What we understood when we signed up is that this is a job, and we were raised to believe in serving something beyond ourselves,” Brian Cotter said.