In some societies and communities the traditional balance between ethnic or religious groups may change due to marked differences in population growth. Groups traditionally integrated as minorities may appear to threaten and destabilize the balance of a society by acquiring equal or majority status.
In Northern Ireland the rate of increase of the Catholic population is reported in 1993 to be accelerating. In 1991, it was estimated that Catholics constituted approximately 42% of the population. At the current rate, Catholics and Protestants could be equal in number by the year 2025, presaging eventual domination by the Catholics. The black and Asian population within the UK was estimated in 1994 to be likely to double its level of 2.7 million within a generation before stabilizing at a figure representing not more than 10% of the whole population.
Whites in the USA will be virtually outnumbered by other ethnic groups, by the middle of the next century. Where whites of European descent now make up about three-quarters of the population of the USA, that will have fallen to about 53% by 2050, and Hispanics will overtake blacks as the country's second largest group in about 2013. The shift in ethnic balance is attributed partly to dramatically improving fertility levels among US women -- the fertility rate has already jumped from 1.8 births per woman to 2.1 births -- and, more significantly, to surging immigration, legal and illegal. By 2050, the number of Hispanics is expected to have quadrupled to about 80 million, about one-fifth of the projected population, and the number of blacks will nearly double to 62 million, or 16% of the population. The decline in the relative presence of whites will make a nonsense of the current social terminology of "majority" and "minority" groups. The revision has much to do with new estimates of likely population influxes from abroad. Where it was once assumed that about 500,000 immigrants would enter the country annually in the foreseeable future, it is now thought the figure will be closer to 900,000. Restraints on illegal immigrants appear to be having little effect.