Danish Act of Succession referendum, 2009

A referendum on changing the Danish Act of Succession, the rules governing the succession to the Danish throne, was held in Denmark, the Faroe Islands, and Greenland on 7 June 2009, simultaneously with the election to the European Parliament, in Denmark proper.

The law, which passed with 85.4% of the popular vote, eliminates male-preference primogeniture in favour of absolute primogeniture, resulting in sons losing precedence over daughters in the line of succession. The law did not affect anyone in the line of succession at the time of the election: the Queen's two children are both male, as is the Crown Prince's eldest child, born in 2005. However, had the referendum not been successful, Prince Vincent, who was born in 2011, would have been higher in the line of succession than Princess Isabella, born in 2007.

Under the rules for change of constitution, the law must be passed by two Parliaments, before and after an election, and then approved by a referendum. The law was passed in 2006 with only one abstention (Simon Emil Ammitzbøll of the Social Liberal Party, who later formed his own party, Borgerligt Centrum). The law was passed again by the new Folketing elected in 2007 on 24 February 2009 with two abstentions (of the left-wing Enhedslisten). It was then submitted to a referendum.

...
Wikipedia