The terms ‘shadow economy’ and ‘grey economy’ are often used interchangeably. The English term ‘shadow economy’ is probably to blame. But ‘shadow’ is not really ‘grey’. In this text, the shadow economy does not refer to illegal or semi-legal economic activity, but to the ageing economy. In 2000, the average age of the Czech population was 37.5 years. This year it is already more than 43 years old and in 2050 the average age will exceed 47 years. On the one hand, improving healthcare, lifestyle, diet and other factors are extending human life. On the other hand, fewer and fewer children are being born. Last year, only 84,000 babies were born, the fewest since 1806, when the time series for this indicator begins. This year it could be even less than 80 thousand, according to an estimate by Hospodářské noviny. Only immigration is responsible for the moderate population growth; the natural increase has been negative for six years in a row. The senior dependency index (the number of people aged 65 and over divided by the number of people aged 20-64 times 100) reached 22.0 at the beginning of the millennium. It now stands at 35.6, and by mid-century it will be 54.4. This means that in 2020 there will be five working-age people for every pensioner, while 50 years later there will be fewer than two. The economic consequences are obvious. An ageing population reduces the available workforce. In 2020, the number of people aged 20-64 was 6.5 million. This year it is 6.3 million and in the next year it will be only 5.7 million. At the same time, the costs of three key systems in society are rising: the pension system, the long-term care system for the elderly and the health care system. Spending on old-age pensions will exceed CZK 600 billion for the first time this year and already accounts for more than a quarter of total state budget spending. Spending on long-term health care amounts to CZK 76 billion. And they will grow rapidly as the population continues to age. Not having children is simply expensive.