In the mainly Protestant Oldpark neighborhood of north Belfast, newly renovated houses stand silent and empty, waiting for families who will never come.
Across the nearby 12-foot-high brick fence, the so-called peaceline, children in the Catholic Ardoyne neighborhood ride bikes and kick balls along bustling streets where families of up to nine people are crammed into tiny, two-bedroom homes.
Bursting Ardoyne and silent Oldpark illustrate a new demographic reality that could have dramatic implications in a province that has endured 30 years of sectarian strife: The Catholic population is rising at a faster rate than that of Protestants.
Census figures to be released this summer are expected to show that, if current trends continue, the size of the Protestant and Catholic communities in Northern Ireland is likely to draw even within 20 years.
The prediction by demographers of a coming 50/50 Protestant/Catholic split has come as a seismic shock to the Protestant community. Protestants, who support the current union with Britain, will soon have to adjust to living in a state where their Catholic neighbors, who wish to be united with the rest of the island of Ireland, are equal in strength, or even more numerous.
"The debate is no longer whether the two communities will ever reach the same size, but what will happen after they do," says Colin McIlheney, head of research at the Belfast office of PriceWaterhouseCoopers, who has studied census figures for 25 years.
A Catholic majority, however, is no guarantee of a united Ireland. About 10 percent of Catholics now support the union with Britain and may do so even when their community draws even numerically with Protestants, says McIlheney.
Dr. Brian Feeney, a former Belfast city councillor for the moderate Catholic party, the SDLP, and now a commentator on social change, says: "The figures mean the rival communities may have to embark on a 'charm offensive' to persuade each other of their respective causes - whether that be the status quo or a united Ireland."
The alternative could be a retreat from peace efforts here, and a society even more divided by bitterness, distrust, and violence, says Dr. Rick Wilford of the politics department of Queens University, Belfast.
"Young Catholics have bought into the  Good Friday peace agreement as a transition to a united Ireland, which they believe can be achieved within a generation," Professor Wilford says.
"On the opposite side you have young male Protestants who are even more opposed than the older generation to a united Ireland. You can see that from the increasingly militaristic murals on the walls around Belfast, and from the fact that unionists who voted strongest against the Good Friday peace agreement were concentrated in this group."
Professor Wilford says that a Queen's University survey last year showed that, although 70 percent of Protestants would probably live with a united Ireland if they had to, 30 percent would never accept a united Ireland under any circumstances.
Some among the Protestant political leadership here have refused to acknowledge the demographic trends. Stephen King, an adviser to the Ulster Unionist leader David Trimble, rejects the inevitability of an imminent 50/50 split, saying "We believe this is the end of a trend, not the beginning."
Northern Ireland, with a current population of 1.7 million, was created in 1921 from the island's six northeastern counties, where Protestants were concentrated, to retain the new state's link with Britain. For most of the past century, the unionist/Protestant majority held steady. The unwritten assumption underpinning Protestant political domination was a belief that Catholics would always be a minority.
Protestants have yet to come to terms with the new demographics - partly because, until this year, there were two distinct camps within the small number of academics and statisticians who study population trends in Northern Ireland.
One camp insisted that the Protestant majority would continue indefinitely, despite a higher Catholic birth rate, because of smaller Catholic families after the mass availability of contraception. The other said Catholic family sizes in Northern Ireland still remained larger than the Protestant equivalent and pointed to the relatively high number of Protestant middle-class students in British universities who never returned home after graduating.
Now both camps agree that a 50/50 Protestant/Catholic breakdown is inevitable, perhaps within 10 years but almost certainly before the year 2020. The Protestant population is also older - 10,000 die every year, compared with 5,000 Catholics.
The official census figures will be released later this year, but other indicators already support the expected statistics. There were 173,000 Catholic schoolchildren last year, compared with 146,000 Protestant. Northern Ireland's three largest cities - Belfast, Derry, and Armagh - all now have Catholic majorities.
In last year's general election, 44 percent of voters supported the two parties who desire a united Ireland: the Social Democratic and Labour Party, and Sinn Fein (up 4 percent from the 1997 general election).
This year's census is expected to show that between 44 and 46 percent of Northern Ireland's population is Catholic. The last census was in 1981, but since many Catholics boycotted it, the results were flawed.
Professor Wilford says the recent economic "miracle" in the Irish Republic, along with increasing secularization and the decline of the authority of the Catholic Church, has made the prospect of a unified Ireland less frightening for the Protestant middle class, although a debate has yet to begin in working-class areas.
The mainly Catholic SDLP is deeply uneasy with any discussion about birth rates and demographic trends, fearing the predictions could rattle Protestants. But Sinn Fein, seen as the political wing of the Irish Republican Army, is eager to highlight the trends and predict the possibility of a united Ireland before the centenary of the Easter Rising of 1916 (which kicked off the war of independence and the partial breaking of the link with Britain).
Under the Good Friday agreement, a key section of the Government of Ireland Act, by which Britain governs Northern Ireland, was repealed. The British government now has no option but to legislate for Irish unity if a majority of Northern Ireland's residents approve it in a referendum.
Most opinion polls in Britain show its people have little desire to hold on to its troublesome and costly "last colony." The most recent survey, for The Guardian newspaper in August 2001, showed that only 1 in 4 Britons wants Northern Ireland to remain part of the country, with 41 percent supporting the province's joining the rest of Ireland.