Sub-replacement fertility

Sub-replacement fertility is a total fertility rate that is not high enough to replace an area's population. In developed countries sub-replacement fertility is below approximately 2.1 children per woman's life time, but the threshold ranges from 2.5 to 3.3 in developing countries because of higher mortality rates. Taken globally, the total fertility rate at replacement is 2.33 children per woman. 2.33 children per woman includes 2 children to replace the parents, with a third of a child extra to make up for the different sex ratio at birth and early mortality prior to the end of their fertile life.

Replacement level fertility in terms of the net reproduction rate (NRR) is exactly one, because unlike the TFR, the NRR takes both mortality rates and sex ratios at birth into account.

Today about half the world lives in nations with sub-replacement fertility. This includes most nations of Europe, the United States, Canada, Australia, Russia, Turkey, Kazakhstan, Iran, Tunisia, Algeria, Lebanon, China, Japan, and many others. The countries or areas that have the lowest fertility are Hong Kong, Macao, Singapore, Taiwan, Ukraine and Lithuania. Nonetheless most of these countries still have growing populations due to immigration and population momentum. Only a few countries have severe enough or sustained sub-replacement fertility (combined with other population factors like immigration) to have population decline, such as Russia, Japan, Lithuania, and Ukraine.

Causes
There have been a number of explanations for the general decline in fertility rates in much of the world, and the true explanation is almost certainly a combination of different factors. The growth of wealth and human development are undoubtedly related to this phenomenon.

The increase of urbanization around the world is considered by some a central cause. In recent times, residents of urban areas tend to have fewer children than people in rural areas. The need for extra labour from children on farms does not apply to urban-dwellers. Cities tend to have higher property prices, making a large family more expensive, especially in those societies where each child is now expected to have his own bedroom, rather than sharing with siblings as was the case until recently. In Mediterranean countries where parents will be expected to buy a house for their daughter when she gets married, there is a powerful financial disincentive to having more than one daughter. Rural areas also tend to be more conservative with less contraception and abortion than urban areas.

Changes in contraception are also an important cause, and one that has seen dramatic changes in the last few generations. Abortion has been legalized in much of the world and contraception has become far more accepted.

The rise of feminism is also viewed as a crucial cause by many. Growing female participation in the work force has led to many women delaying or deciding against having children, or to not have as many. Relations between the sexes have become more competitive and less stable. A longer pursuit of education also delays marriages. Greater access to abortion and contraception, and greater proclivity of feminist-influenced women to use them, also can reduce rates.

Other social changes both separate and related to feminism also have played a role. Bearing children is regarded as less of a social duty than it once was in many societies. Women's social status increasingly correlates with their work or behaviour as consumers rather than from their role as mothers. Indeed having a large family is often socially deprecated, being associated with lower status groups. A number of governments such as those of China and Iran have launched programs to reduce fertility rates and curb population growth. (See One-child policy in China and Family planning in Iran.)

Another school of thought argues that all these factors are a natural outgrowth of a Malthusian attempt to restore a population balance that was upset earlier. The revolution in hygiene and medicine that caused death rates to plummet during the twentieth century did not see a corresponding fall in birth rates until a couple generations later. This period of low death rates and high birth rates thus caused human population to balloon at a rate never before seen in human history on such a wide scale. The Malthusians argue that modern low birth rates are a natural reaction to counteract this imbalance.

Another, perhaps simpler explanation, could be a reduction in the frequency of sex in populations with low birth rates. For example, according to a survey published by the Japanese Family Planning Association in March 2007, a record 39.7 per cent of Japanese citizens ages 16-49 had not had sex for more than a month. . The decline of male sperm counts in industrialised countries over the past forty years is also often cited as a possible cause.

Widespread availability of pornography through the Internet and other mass media channels can satiate the sexual desires of men and reduce sexual intercourse, thereby reducing fertility.

Effects
Sub-replacement fertility do not immediately translate into a population decline because of population momentum: recently high fertility rates produce a disproportionately young population, and younger populations have higher birth rates. This is why almost all nations with sub-replacement fertility still have a rapidly growing population, because a large fraction of their population are at the beginning of their child-bearing years. But if the fertility trend is sustained and not compensated by immigration, it results in population ageing and population decline. This is forecast for most of the countries of Europe and East Asia, where immigration is low.

Current estimates expect the world's total fertility rate to fall below replacement levels by 2050, although population momentum will continue to increase global population for several generations beyond that. The promise of eventual population decline helps reduce concerns of overpopulation, but many believe the Earth's carrying capacity has already been exceeded and that even a stable population would not be sustainable.

Sub-replacement fertility can also change social relations in a society. Fewer children tends to mean each child gets more attention from the parent. Fewer children, combined with lower infant mortality has also made the death of children a far greater tragedy in the modern world than it was just fifty years ago. Having many families with only one or two children also reduces greatly the number of siblings, aunts and uncles.

Population aging poses an economic burden on societies, as the number of elderly retirees rises in relation to the number of young workers. This has been raised as a political issue in France, Germany, and the United States, where many people have advocated policy changes to encourage higher fertility and immigration rates. In France, payments to couples to have children have increased birthrate. Subsidizing childbirth, however, can erode government funds needed to finance pensions or health services for an ageing population, which may mean the financial burden may fall upon future generations in the form of higher taxation.

Forecast
In recent years some European countries have seen gradually increasing fertility rates, most notably France: the total fertility rate of metropolitan France alone increased to 1.98 in 2006, while the total fertility rate of metropolitan France and the overseas departments combined has reached 2.00 that same year. Nevertheless even France remains below the 2.09 children/woman fertility rate of the USA. Other European governments, fearful of a future pensions crisis, have followed the French example in an attempt to encourage more women to have children. Measures include increasing tax allowances for working parents, improving child-care provision, reducing working hours/weekend working in female-dominated professions such as healthcare and a stricter enforcement of anti-discrimination measures to prevent professional womens' promotion prospects being hindered when they take time off work to care for children. The result has been a slight increase in the fertility rate in countries such as Britain and other northern European countries but the increase has nowhere been large enough to reach replacement level.

Attempts to increase the fertility rate among working (esp. professional) women bring difficult political dilemmas; how far to alter traditional working practices so that women who are juggling work and child-raising responsiblities are not disadvantaged in their careers compared with men (for example, by legislating for compulsory paternity leave, flexible working and/or limiting total weekly working hours for men as well as women) and above all the question of whether the problem of sub-replacement fertility is so serious that unmarried women should also now be encouraged to have more children.

Giving women unpaid maternity leave can have the unintended negative consequence of dissuading employers from hiring women because they may fear having to pay a pregnant woman wages for a job she isn't doing. This may increase the gender-wage gap, the income disparity between men and women in the labor force.

The American exception
While almost all of the developed world, and many other nations, have seen plummeting fertility rates over the last twenty years, the United States' rates have remained stable and even slightly increased due to the high fertility rate among recent immigrant communities such as Hispanics. The fertility rate among non-Hispanic whites in the US is around 1.9, ie slightly below replacement level.

A regional breakdown of the United States thus closely mirrors the distribution of Hispanic immigration. New England has a rate similar to most Western European countries and the South and border states have fertility rates considerably higher than replacement. States where The Church of Jesus Christ of Latter-day Saints has a strong presence, most notably Utah, also have higher-than-replacement fertility rates, especially among the LDS population.

The Israeli exception
The United States is not the only western nation with a high fertility rate. Israel has a fertility rate of 2.84 children per woman (the highest in the developed world). This high FRT is due in part to the high fertility rates of the Arab citizens of Israel (4.2), and the extremely high rates of its Ultra-Orthrodox, Haredi Jewish citizens (over 8). The total fertility rate of Israel's Jewish residents is 2.7. The lowest fertility rate of any religious group in the country is among the Christian Arab citizens of Israel (1.71).