One interesting thing about the British royal family is the power of a still-wrinkled baby to render his swashbuckling, helicopter-piloting uncle somewhat superfluous.

Entering the world with such fanfare, Prince George Alexander Louis of Cambridge has just knocked red-haired Prince Harry, the younger brother to Prince William, a very big step back in the line of succession, from third to fourth. And Harry will continue to backpedal away from the crown if proud dad William and Duchess Kate decide to have more little Cambridges.

Or "spares," as they are called in the palaces.

In the old days, these extras were a bit more important than today. That was back when the royal cousins and such crowded into the wings of the court, keeping sharp objects about their persons, when princes could disappear in the Tower of London and when brood queens found their necks on the block for failing to produce a male heir.

It was wise then to keep an eye on all those Shrewsburys, Mortimers and Seymours. Today the biggest threat seems to be disloyal butlers, phone tappers and paparazzi.

Monarchs are hardly born every day, which explains the journalistic excitement about the royal wee one.

But as Charles, Prince of Wales, might advise the new grandson: Don't get the royal nappies in a twist. Being born near the throne doesn't mean you'll sit on it anytime soon. As Elizabeth's oldest child at 64, he has waited longer than anyone in English history for the crown to be plopped on his head, Charles is very much aware of the longevity gene of the House of Windsor — his mother is 87 and seems uninterested in abdicating her waving spot on the balcony; her mother made it to 102.

Think about this. If William, now 31, becomes king and lives as long as his grandmother, it might be 2069 before his son's coronation.

"This boy is born to be king, but he may have a whole lifetime ahead of him first," royal commentator Hugo Vickers told Bloomberg News. Besides having the run of his great-grandmother's two palaces, two castles and what comes with them, he said, "This child will live an extraordinary life meeting some of the most famous and fascinating people, yet the royal family has learned to give its children as normal an upbringing as possible."

Uncle 'arry — actually Henry Charles Albert David, but known as Capt. Harry Wales in his Apache helicopter regiment — has plenty of role models on how to handle this news with, well, a stiff upper lip.

Besides the Princess Royal, that is, his aunt Anne, there are two uncles, Prince Andrew, Duke of York, and Prince Edward, Earl of Wessex, all unneeded spares. Anne once was fourth in line behind all her brothers, but once they began begatting, she slipped to 11th. Her own son, Peter Phillips, and his two toddlers pretty much bring up the rear of the Buckingham Palace crowd, sans titles, apparently at Anne's request.

Prime Minister David Cameron's baby gift for princesses will have to wait. He was the driving force in 2011 to overturn the rule of primogeniture, which has meant earlier-born princesses had to bow to those annoying baby brothers. Now, whoever gets down the right royal birth canal first wins.

The law is not retroactive, however, so Anne did not move up in line to inherit all those Corgis.

After Elizabeth's brood comes that of her late sister, Princess Margaret, Countess of Snowden, who despite an unhappy marriage left behind a van full of Armstrong-Joneses and Chattos.

So far the count stretches to about 20. You'd think that should do it, but not quite. One mustn't forget Richard, the Duke of Gloucester, the queen's cousin. Are we keeping this straight? His late father, Prince Henry, was younger than Prince Albert (the stutterer in "The King's Speech"), a spare lug-nutted onto the throne as George VI, when his big brother, who was destined to not become King Edward VIII, abdicated to marry an American divorcée.

The Gloucesters, anyway, are important in case an asteroid strikes St. James' Park. In the case of a second asteroid, one should not dismiss the line of the 77-year-old Duke of Kent, another cousin of the queen. His son, George, the Earl of St. Andrews, had been barred from ever getting his pillows fluffed at Buckingham Palace because he married (gasp) a Catholic. But now, because of Cameron's new rules, that has been changed.

So, George, get back in line, the very back, please.