
The European population is entering a new phase of its demographic history, characterised by long-term decline and accelerated ageing. The dynamics of the demographic transition have led to increased longevity and declining birth rates, resulting in profound changes to the population structure. The reduction in mortality risks from birth to old age has brought the replacement level (the number of children required to replace parents) to around two. However, fertility rates have fallen below this level in most countries worldwide, leading to insufficient fertility to sustain generational replacement.