La Revanche du berceau ("the revenge of the cradle") is a term for demographic threat via high birth-rates among a minority, specifically associated with French Canadians.
The phrase originated in Quebec before the First World War, according to John Robert Colombo's "Colombo's Canadian References." It suggested that although Anglo-Canadians dominated Canada in the 19th century, the higher birth rate in Quebec promised that French-Canadians would resist to the British immigration and discrimination. Implying it won't be possible to discriminate against them if they stay in important number and compete with the English-speaking Quebecers allowed to moved in Quebec while French speaking immigration was forbidden. However, translated as the phrase suggests French Quebecers might somehow avenge or reverse the Conquest of New France by Great Britain in 1759.
Since the Quiet Revolution of the 1960s, however, Quebec has demonstrated an unusually low birth rate, causing anxiety about the future of the culture and people of Quebec.