Many governments face problems of underreproduction and overreproduction. Some governments promote fertility, such as Japan and Armenia. China famously had a one-child policy to curb fertility.

True or not, Churchill has been accused of blaming an Indian famine on the Indians' "breeding like rabbits". This leads me to wonder, under what conditions do governments have a responsibility to curb overpopulation? Many states define the responsibilities of their government in a constitution, but a casual search online turns up no states that mention regulation of fertility in their constitutions, despite the examples of both curbing and promoting fertility. So when would a government be expected to interfere?

  • How could under what conditions do governments have a responsibility to X possibly be objective? Commented Jan 2 at 18:25
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    I doubt it is part of the written duties of any government, so are you talking about the general role of the state in a philosophical way? Eg the US constitution has a preamble that mentions "promote the general Welfare", and maintaining the population structure could be seen as part of "General Welfare".
    – James K
    Commented Jan 2 at 18:25

1 Answer 1


under what conditions do governments have a responsibility to curb overpopulation?

Government often have the authority to device policies to regulate population, but almost never have any enforceable legal obligation, or even unenforceable moral obligation, to do so.

Governments are morally expected to further the general well-being of their people, and population levels may figure in to that, but little more.

Also, as more and more countries see their annual births fall below their annual deaths, "overpopulation" is often not what they are worried about.

Concern about overpopulation faded when it became clear that demographic transition from having births at more than the replacement rate to less than the replacement rate, was essentially universal, and quite rapid, in countries that reach a certain threshold of economic development (for reasons that are still not fully understood). The very disruptive effects of China's "one-child policy" also discouraged policy efforts to reduce overpopulation.

enter image description here

Countries in green have stable populations (based on TFR, total fertility rate), those in blue have declining populations in the long run based upon current births, and those in red have growing populations in the medium to long run based upon current births.

(Wikipedia image source).

A more direct measure of population growth and decline is here (with the reverse color scheme and including immigration effects):

enter image description here

  • The plot does not show which countries have growing, declining, or stable populations, but rather, I suspect, which of them have an asympotically stable or unstable average number of children born per birthing parent. That is why the break-even point is around 2. But because of that distinction, many of the populations with reproductive number below 2 are in fact still growing (like the USA).
    – Obie 2.0
    Commented Jan 2 at 20:36
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    @Obie2.0 Strictly speaking the chart is of total fertility rate (which has a technical definition but is roughly children per woman per lifetime converted to a point in time measure). The replacement rate in modern conditions is 2.1. Deeper in history, the replacement rate was about 4, with the average woman having one child die in infancy, one as a child, and two making it to adulthood, and about 1% of births resulting in the death of the mother. A TFR of 4 requires about 6+ pregnancies per lifetime due to miscarriages. In practice, a TRF of 2.3+ is almost always implies population growth.
    – ohwilleke
    Commented Jan 2 at 20:40
  • Which is precisely why the graph does not show which countries are growing or declining, only a measure of asymptotic behavior. For instance, for the USA, the birth plus immigration rate currently exceeds the death plus emigration rate, which is also true of many of the other lighter blue countries (actually, the birth minus death rate by itself is net positive, even before considering movement). That is the actual measure of whether a country's population is currently growing or declining.
    – Obie 2.0
    Commented Jan 2 at 20:41
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    @Obie2.0 that's where the "in the long run" comes from. Korea, for example, had below-replacement-rate birth rates for a while, but only just now started to have negative population growth. It takes time for low birth rates to become negative population growth because, if there was previous population growth, there are simply more young people having kids than older people dying. However, assuming current trends (which we have no reason to believe will drastically change) the eventual result is population decline.
    – Esther
    Commented Jan 2 at 21:07

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