For all the scientists who have spent decades trying to decipher the DNA helix, all the research biologists hunched over microscopes in sterile laboratories attempting to unlock a potential Pandora's Box with human cloning, here's a simple suggestion.

Quit fretting over funding and research grants and invest a couple of bucks in a long-distance phone call to Clay Matthews Sr., a man who knows a thing or two about bloodlines and whose sons have the NFL résumés to prove it.

	Bruce Matthews played all five positions on the offensive line during his 19-year career.

When offensive lineman Bruce Matthews of the Tennessee Titans announced Monday that he's retiring from the NFL after 19 seasons, opting after 296 games to spend more time with wife Carrie and the couple's six kids, it ended a league lineage that doesn't figure to be approximated anytime soon.

But don't bet against one of the sons of Bruce Matthews or Clay Matthews Jr. playing in the NFL at some point in the not-too-distant future. There is, after all, something to be said for bloodlines. And when it comes to producing NFL thoroughbreds, in terms of on-field performance and overall class, the Matthews family is a vein every bit as fertile as a river of gold.

How else to explain that Bruce Matthews retired with more appearances than any non-kicker in league history? Or that older brother Clay Matthews Jr., even six years after retiring from a 19-year career of his own, still holds the record for most games played by a linebacker and rates eighth on the all-time appearances list?

"Whatever they've got, the family ought to bottle it and sell it, because they'd make a fortune," acknowledged Titans coach Jeff Fisher. "Whatever it is, it's the right stuff, since that family has certainly set a good example for the NFL for a long time. I'm sure it all gets back to their upbringing. You can see they sure had a solid foundation."

When it comes to NFL tenure, Clay Matthews Sr. was a relative piker compared to his two sons. The senior member of the clan contributed just four of the family's 42 aggregate league seasons and only 45 of the 619 games in which they played.

But Clay Matthews Sr., a onetime All-American end at Georgia Tech and a member of that school's athletic Hall of Fame, led by example. The senior Matthews is described in various newspaper clippings as "gritty," "determined" and "diligent." Those qualities, along with a sense of civility, were traits he passed on to his sons.

In 1996, at a Georgia Dome ceremony marking the retirement of Clay Matthews Jr., after two seasons with the Atlanta Falcons at the tail-end of a career that included five Pro Bowl appearances, all three Matthews men gathered at the 50-yard line for a tribute. There wasn't a dry eye among the bunch, not so much for what was transpiring that day, but for the hours of re-hashing that preceded it that afternoon.

	Family Tradition
	Bruce Matthews ends his career having played more games than any non-kicker in NFL history, and his 19 seasons with the Titans franchise are tied for the second-most for a player with one team. Only three kickers, George Blanda (also a QB), Gary Anderson and Morten Andersen, have played more games NFL games. Bruce's brother Clay ranks fifth on the non-kicker list, having played nearly 280 games in his 19-year NFL career.
		Games
	Bruce Matthews	296*
	Jim Marshall	282
	Trey Junkin	281
	Darrell Green	279
	Clay Matthews	278
	*4th-most in NFL history

The retirement of Bruce Matthews conjured up some memories for this writer, who was privileged to have spent time with the trio and other members of the family on that day, and who was moved by the mutual respect and love they shared.

While there can't help but be some physical connection among the three members of the Matthews family that played in the NFL, their cumulative success was also a function of some of the rules by which they lived their lives away from the game. There were always some things, Clay Matthews Jr. acknowledged, that were intractable. Foremost was the understanding that a Matthews man never shirks his duty and never walks away from a job undone.

There was a time in high school when Bruce Matthews told his father he was tired of playing on the varsity basketball team and wanted to turn in his uniform. Clay Sr. had none of it, even if it meant Bruce sat at the end of the bench, because Bruce had committed to his coach and his teammates and was not about to abandon them.

"It's a very simple story," Clay Sr. recalled. "I had a set of rules I could use on all of my kids. I told all of them, 'You can do whatever you want to. You can go and play any sport that you want to. You can go out and try anything you want. But there are two rules that you cannot ignore.'

"One of them is, 'I don't care if you're on the last string and sitting on the bench all of the time and are the worst guy out there, you can't quit.' And No. 2 is, 'If I ever see you play or practice and you're not giving 120 percent, I'll yank you out of there myself.' I think they all pretty much got the message."

Loud and clear, apparently, and with no need for repeating.

That's why it is not surprising that Bruce Matthews, who remarkably started at least 17 games each at all five offensive line positions and never missed a game because of injury, leaves behind such a wondrous legacy. They are tough guys, these Matthews guys, well-spoken and articulate and giving of their time, but also blessed with a determination that nearly belies their off-field veneer.

The grittiness was honed in the family basement, where Bruce and Clay Jr. played hockey with a regulation puck but no pads or masks. They invented a game in which they used a 2x4 as a bat, and darts as a ball, the goal of which was for the batter to connect with the dart and make it stick in the piece of wood. When they played one-on-one hoops out in the driveway, the standard rule was that drawing a stream of blood was the only thing worthy of a foul call.

Somehow amid the capriciousness of youth, the love of all sport, the Matthews boys found time for education and, more significant, for assimilating the values that would later serve as the foundation of their respective professional careers.

"It was," allowed Clay Matthews Jr., "a great upbringing."

That's why five years from now, when the electors vote Bruce Matthews into the Hall of Fame, they might consider going one step beyond the normal bronze bust. They ought to cordon off a section of the Canton, Ohio shrine and assemble an exhibit devoted to the entire Matthews clan.

It is, after all, an All-American family in every sense of the term.

Len Pasquarelli is a senior writer for ESPN.com