Istanbul is a prime example that most clearly demonstrates the impacts of urbanization/metropolization and migration on the population growth rate.Indeed, even in districts such as Esenyurt, Sultanbeyli, and Arnavutköy, which have dense eastern and conservative populations, the fertility rate hovers around 1.48, the national average of Turkey.At the same time, it has fallen even below 1.0 in 9 districts of Istanbul; no district reaches the replacement-level fertility rate of 2.1, which is considered necessary for population renewal and sustainability.