When Prince William and Kate announced they were expecting their first child in 2012, the appetite for royal baby news seemed insatiable.

Three years on, interest surrounding the young royals' second child — a younger brother or sister to George — is notably more subdued. Part of it may be that the novelty of seeing "Kate and Wills" as parents has worn off. But it's also inevitable given the royal succession rule, in which the throne always passes to the eldest child. Second-born royals in the line of succession rarely have to worry about one day becoming king or queen — they are known half-jokingly as the "spares to the heir."

It's a position that brings far less responsibility, but also fewer privileges than those enjoyed by the heir apparent. It's also one that attracts relentless public scrutiny.

While eldest children have their destinies carved out from birth, many royal "spares" have struggled to find meaningful public roles.

"It's always been a rather unenviable situation. There are often shades of jealousy, evident in the current queen and her sister," said Joe Little, managing editor at Britain's Majesty magazine, referring to Princess Margaret and Queen Elizabeth II.

Not all younger royal children spend their lives waiting in the wings, heading charities and cutting ribbons. Elizabeth's grandfather, George V, inherited the throne in 1910 after his elder brother died of pneumonia. George VI, another second son, became king after his brother abdicated in 1936.

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PRINCE HARRY (born 1984)

The second son of Prince Charles and Diana, Harry is often seen as the mischievous one, the fun-loving counterpart to the more staid — some say dull — William.

Harry came of age under full public scrutiny, and through the years he has sparked some scandalous headlines. He admitted to smoking cannabis and drinking in his teenage years, and in 2004 he was photographed scuffling with a photographer outside a London nightclub.

A couple of incidents were particularly embarrassing for the royals: When the prince was photographed wearing a Nazi-themed costume to a fancy dress party, prompting the headline "Harry the Nazi," and more recently when he was pictured partying naked in Las Vegas.

Like many other royals, Harry chose a military career and has served in Afghanistan. That will likely continue to be his main role as he gets bumped further down the line of succession. The new royal baby will see Harry relegated to fifth in line.

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PRINCE ANDREW (born 1960)

Andrew, the queen's second son and Charles' younger brother, gets more press than fellow siblings Anne and Edward — but for all the wrong reasons.

The prince enjoyed a successful naval career as a helicopter pilot and served in the Falklands War, yet that record has been overshadowed in recent years by headlines about his friendship with several controversial figures, notably U.S. financier Jeffrey Epstein, a registered sex offender. Andrew stepped down from his role as a trade envoy in 2011 as questions mounted, and this year he had to publicly deny claims that he had sex with an underage woman.

Andrew, who is divorced from Sarah Ferguson — known as Fergie — has also long been criticized for his opulent, globe-trotting lifestyle, and his romantic links to a number of models and starlets have attracted unwelcome nicknames like "Randy Andy."

Andrew will become sixth in line to the throne with the baby's birth.

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PRINCESS MARGARET (1930 -2002)

Four years younger than the queen, Margaret was Elizabeth's only sister. With her film-star looks and vivacious personality, Margaret lived a glamorous and sometimes controversial life, and many remember her best for her turbulent romances.

The princess's relationship with divorced pilot Peter Townsend was frowned upon by Winston Churchill and the Church of England, among others. In 1955, aged 25, she declared she had decided against marrying him, "conscious of my duty to the Commonwealth."

Margaret later married photographer Antony Armstrong-Jones, a supposed "commoner," and the couple became the heart of a fashionable set in the Swinging London scene of the '60s and '70s. The princess was often snapped dancing late into the night, threw famous parties in the Caribbean and mixed with pop stars like Mick Jagger.

Before the couple divorced, Margaret met Roddy Llewellyn, 17 years her junior, sparking a relationship that prompted huge media coverage.

Margaret's health declined in her 60s, after a lifetime of alcohol and cigarettes. She died in 2002, aged 71.

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KING GEORGE VI (1895-1952)

The father of the queen, George VI — born Albert — became the unexpected king when his elder brother, Edward VIII, abdicated in 1936 after a reign that lasted just 11 months. Edward, often portrayed as a raffish playboy, had abandoned the throne to marry his mistress, the divorced American socialite Wallis Simpson.

A shy man with a stammer, George had to restore public faith in the monarchy and be the symbolic leader of a country at war with Germany. The Oscar-winning film "The King's Speech," which dramatized the story of how he overcame his initial struggles as monarch, reignited interest in his often overlooked life.

George died aged 56, in 1952.