Irish King Apparently Got Around

This is the time of year when everybody seems to boast of having some Irish blood.

But, observes CBS News Correspondent Mark Phillips, few know just how rich that blood might be.

Full Coverage: St. Patrick's Day

From the bars of County Clare in Ireland, to the bars of New York City, there's a new boast that could very well be true: Not just Irish blood, but royal Irish blood, might well be flowing through Irish men's veins.

A genetic study of Irish men, particularly men from the west of Ireland, has shown that as many as 20 percent of them can trace their heritage to one man, an ancient Irish king from the mists of Celtic history named Naill of the Nine Hostages, who is thought to have had a spectacularly reproductive life.

"Ireland was a Christian country in medieval times," says Trinity College of Dublin genetic researcher Dan Bradley, "but one aspect of the Christian code they didn't take to very warmly was monogamy."

Phillips says this all comes as no surprise to Conor O'Brien, the current acknowledged chief of the Irish clans, known as The Lord Inchiquin.

The O'Brien clan has controlled a sprawling Irish estate for 1,000 years. And on his family tree is that prolific King Naill, who lived in the year late fourth century.

When Phillips remarked that Naill is responsible for the genetic signature in something like one in five Irish men, O'Connor said, "Those kings and influential people of that time did get around a bit!"

At least, Phillips adds, that's the theory, one that's caused some amused bar talk in the local pubs.

In one Irish bar in Ennis, a patron told Phillips, "If some guy tells me his great grandfather was king of Ireland, I'd say, 'You're drunk.' "

"Of course it's true!" another customer exclaimed. "It's Irish."

Using modern science to confirm ancient myth is not only fun, it may have practical consequences, Phillips points out.

If so many Irish men can now claim to descend from a royal line, maybe they can also claim a right to some of the country's grand castles.

Which, O'Brien says, might not be such a good thing "because everyone wants to be a high king, and we'll all be fighting again," he said with a laugh.

As if they needed one, there's now another reason for Irish eyes to smile, Phillips concludes.