The difference in fertility is not limited to differences in age, race, or economic status. Societal factors that play a role in fertility may vary over time, and it is possible that the effects of different policies and programs will be different in different countries. Nevertheless, it is important to keep in mind that comparing fertility across two societies can reveal some fundamental differences between them.
For example, the difference in total fertility between the United States and Canada has not gotten much smaller over the last 10 years. However, this can be explained by the fact that the economy of the US is much larger than that of Canada. Despite the disparity, the average American teenager has a birth rate of 2.5 times that of a Canadian teenager.
There have been many studies on the differences in fertility between racial/ethnic groups, but the best data come from more recent research. In particular, studies of Black and Hispanic women of various races have shown that their childbearing behaviours are similar.
Similarly, a study of the differences in total fertility between different levels of education and economic status did not find that the best way to increase fertility is to improve education, or to lower poverty rates. Instead, the biggest contributor to changing fertility rates is changes in infant mortality and social settings.
Among the OECD countries, fertility has decreased in all but Denmark and South Europe. Those countries are considered moderately low fertility, and have total fertility rates that are between 1.5 and 2.1 births per woman. This trend is reversing in Finland and the Netherlands, which reversed the recent childbirth decline in January.
In comparison, a comparison of fertility between countries with the same demographic and cultural characteristics is more complex. Although there have been some improvements in health, education, and family planning programs in many developing countries, not every country has made enough progress to reach this goal. Moreover, there are other factors that could be more influential than these.
Overall, there have been considerable improvements in the quality of life for people living in developing nations. But there are still some factors that could be more important in influencing fertility, such as the strength of family planning programs, the quality of the economic environment, and the level of infant mortality. These factors have also contributed to the difference in fertility between the U.S. and Canada, but the best data point to the most significant factor.
While there has been a decline in fertility in Canada, the United States, the United Kingdom, and Australia, the difference in fertility has increased in several of these countries. It has been most noticeable for the youngest women. Nevertheless, the total fertility rate has also declined in all of the moderately low fertility countries.
Regardless of the factors that have played a part in the divergence in fertility, it is clear that the impact of improvements in these areas is only a small fraction of the total number of women who have ever been married. And, the divergence in fertility is just one example of a wider social and political trend.