In many Western countries the population has started falling noticeably. Italy and Japan are examples that spring to mind.
In Ulyanovsk, a region of Russia, this is such a worry that for the third year running the governor has declared a special day for couples to stay at home and procreate.
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Demographers estimate that Russia could lose 40 million people - almost a third of its current population - by the middle of the century."
"A combination of falling birth rates, emigration and an ailing healthcare system has led to the decline."
http://news.bbc.co.uk/1/hi/world/europe/6990802.stm
Looking at those I know in the UK, few have more than two children, many have only one. If this is replicated nationwide, then a decline in population size would normally be expected.
If your politicians called on you to get down and dirty with your partner with the aim of a bundle of joy in nine months, would you?