How I hate the title's framing. Greece has no population problem; it has an economic problem. Greeks have not given up on sex; they are simply responding to economic incentives, the same as people everywhere. The interviewed economist, Nikos Vettas, said as much; they just need to increase the country's productivity. If the economy grew at a respectable rate 5̶-̶1̶0̶%̶/̶y̶e̶a̶r̶ instead of flatlining since 2008, they would have no problem.
https://data.worldbank.org/indicator/NY.GDP.MKTP.KD.ZG?locat...