Crown Princess Mary and Crown Prince Frederik of Denmark with Princess Isabella and Prince Christian pose after the christening of their twins, Prince Vincent and Princess Josephine, at Holmens Kirke on April 14, 2011, in Copenhagen, Denmark. / Pascal Le Segretain/Getty Images
News that Prince William and Kate, the Duchess of Cambridge, are expecting their first child means yet another pint-sized heir to the throne will be growing up among all the royals in Europe.
There's been something of a baby boom among the royals in recent years with royal families from Norway to Spain adding to their ranks.
The youngest of these right now is Sweden's Princess Estelle, born in February to Crown Princess Victoria and Prince Daniel, Duke of Vastergotland. She is second in line, after her mother, for the crown now worn by her grandfather, King Carl XVI Gustaf.
In neighboring Denmark, Crown Prince Frederik and his Australian wife have four children, the youngest of them twins, Prince Vincent and Princess Josephine, born in January of 2011. They also have a son and heir, Prince Christian, born in October of 2005, and a daughter, Princess Isabella, born in July 2007. Prince Christian is second in line after his father for the throne now occupied by his grandmother, Queen Margrethe.
The queen's younger son, Prince Joachim, also is a new dad . His daughter Princess Athena was born in January. Joachim also has a son, Prince Henrik, born in May of 2009 with the French Princess Marie, his second wife. He has two sons, Prince Felix (born July 2002) and Prince Nikolai (born August of 1999), with his first wife.
In Norway, Crown Prince Haakon has two children: Princess Ingrid Alexandra, born in January 2004, and Prince Sverre Magnus born in December 2005. The prince also is stepfather to Princess Mette-Marit's son, Marius Hoiby. Princess Ingrid is second in line for Norway's throre, now held by her grandfather, King Harald.
Belgium's Crown Prince Philippe and his wife Princess Mathilde have four children: Princess Elisabeth, born October 2001; Prince Gabriel, born August 2003; Prince Emmanuel, born October 2005; and Princess El?onore, born April 2008. Princess Elisabeth will inherit the throne, now occupied by her grandfather, King Albert, from her father.
Crown Prince Willem Alexander of the Netherlands and his Argentine wife, Princess Maxima, have three daughters - Princess Catharina-Amalia, born December 2003; Princess Alexia, born June 2005; and Princess Ariane, born April 2007. Behind her father, Princess Catharina-Amalia is second in line for the throne occupied by her grandmother, Queen Beatrix.
Spain's Crown Prince Felipe has two daughters, Princess Leonor, born in October of 2005 and Princess Sofia, born in April of 2007. Princess Leonor is second in line to the Spanish throne behind her father.The Spanish monarch is King Juan Carlos.