A leading academic has claimed Catholics could outnumber Protestants in Northern Ireland as soon as 2021.
Dr Paul Nolan specialises in the peace process and told the BBC Catholics could soon make up the majority of the population.
"Three years from now we will end up, I think, in the ironic situation on the centenary of the state where we actually have a state that has a Catholic majority," Dr Nolan said.
"The future of unionism depends entirely upon one thing - and I mean unionism with a small 'u' - it depends on winning the support of people who do not regard themselves to be unionists with a capital 'U'.
"In other words people who do not identify with the traditional trappings of unionism; people who would give their support for a UK government framework and that's a sizeable proportion of Catholics provided they are not alienated by any form of triumphalism or anything that seems to be a rejection of their cultural identity as nationalists."
While Dr Nolan said that he anticipated there would be greater discussion surrounding a united Ireland in the coming years, he said that Protestants should not be alarmed as being a Catholic did not automatically make someone in favour of a United Ireland.
The last census in Northern Ireland in 2011 showed that 48% of the population was Protestant and 45% Catholic.
Data from 2016 says that the only population group in which Protestants still outnumber Catholic's in is the Over 60's with 57% Protestants compared to 35% Catholics.
The same figures show that of those at working age 40% are Protestant with 44% Catholic.