Army Sgt. Chris Meis isn't a sentimental man, but having his son Caleb nearby helps beyond words as they serve together in Afghanistan, thousands of miles from home.

"I can't imagine deployment without him," the elder Meis told FoxNews.com by phone from combat post Rahman Kheyl, about 75 miles south of Kabul. "It's been such a good experience to have him here with me."

Meis, 47, a carpenter by trade, spent three years in the Iowa National Guard in the 1980s before re-enlisting in 2007. His 19-year-old son, Pvt. 1st Class Caleb Meis, would join three years later. The father-son duo from St. Charles, Iowa, is now assigned to different platoons within Charlie Company 1-168, 2nd Brigade Combat Team, 34th Infantry Division, an arrangement that keeps them connected, but not too close for comfort.

"We normally see each other every day and spend quality time together maybe once or twice a month," Chris said. "We play chess every once in a while. He plays a lot of video games and lifts a lot of weights, like the other young kids do."

On Father's Day, however, the Meises won't get to reminisce in person about their shared military career. That'll come later, perhaps beginning this summer when the Meises are due to return to Iowa.

"I am not real sentimental about holidays," Chris Meis said. "I appreciate 'em when they come around, but I'm honestly not going to miss Father's Day other than the fact that I won't be around my son."

On Sunday, Sgt. Meis will be in Gardez, Afghanistan, the capital of its Paktia province. As of now, Caleb says he has no specific plans on how to mark the holiday, but that's subject to change.

"It's not like we have any kind of store to go to," Caleb said about buying his father a gift.

While all U.S. military branches are stocked with fathers, mothers, brother and sisters, the Meises are among a select group of service members who serve alongside their relatives. Military spokesmen were unable to supply specific numbers for how many active-duty soldiers currently serve with their sons or daughters, but they told FoxNews.com that the configuration is rare.

Following the deaths in 1942 of five Iowa brothers on the USS Juneau during World War II, the topic of close relatives serving together in combat was examined by Congress, which considered proposals to ban siblings from being assigned to the same unit. No bill eventually passed, however.

Each military branch handles such relationships differently, and the uniqueness of such close family affairs has been well-chronicled, dating back to the Sullivan brothers who died on the Juneau.

For example, in Parwan Province, Afghanistan, U.S. Army Staff Sgt. Wade Corell, of Strawberry Point, Iowa, currently serves alongside his father, U.S. Army Col. Benjamin Corell, the commander of the 2nd Brigade Combat Team, 34th Infantry Division. Along with the Meises, the Corells are part of some 2,800 Iowa National Guard soldiers currently serving in Afghanistan, the largest deployment since World War II, Army officials told FoxNews.com.

And U.S. Army Maj. Benjamin Rex celebrated Father's Day in 2009 with his son, Pfc. Jeromy Bruce Rex, while stationed in Baghdad, an experience the younger Rex said he'll never forget.

"It's been really great having him here because he encourages me to do better," Jeromy told the Army's official website. "I'm just really glad to share this experience with him. I feel it's going to bring us closer as father and son, and hopefully someday after he gets out of the military, I can step up and fill his huge shoes."

Like Jeromy, the younger Meis said he's grateful to have been able to cultivate his relationship with his father in a way that most men will never do.

"Other guys I've talked to about it always say they couldn't imagine having their Dad on deployment with them," Caleb said. "But I've had somebody who I can go talk to and identify with much more closely than other guys.

Caleb said his always-solid relationship with his father has "definitely" gotten better while in Afghanistan, and he intends to continue cultivating that bond when they return home this summer. Caleb then plans to start classes at Des Moines Area Community College and marry his fiancee, Sarah.

"Time cannot go fast enough," Caleb said.

Chris Meis, meanwhile, will probably return to carpentry. But the father and son will always have Iowa's Camp Dodge, where they'll continue to conduct drills as part of the National Guard.

"So we'll still be together," Chris said. "We don't anticipate any separation."

For his part, Chris said he'll call his father David on Sunday, and later his wife of 24 years, Karla. And while he's eager to return home to reunite with his three other children -- Erin, 22, Bethany, 17, and Joshua, 15 -- Meis realizes a special chapter with his first-born son is coming to a close.

"Further down the road, when we have time to reminisce, we'll be able to talk about the same experiences," he said. "And we'll both just know."