[NOTE: The below report has been updated to fully include all the new information available in the 2010 Preliminary Birth Data report.]

JESSE POWELL writes:

The National Center for Health Statistics has released the Final Birth Data for 2009 and the Preliminary Birth Data for 2010. The pattern of “risk aversion” presumably in response to the economic crisis is continuing. The ratio of births out-of-wedlock grew slowly from 2007 to 2010 but during this period fertility and the proportion of women of reproductive age who were married fell sharply. “Risk Aversion” can explain the decline in fertility among both married and unmarried women as well as a reluctance to get married which might explain the proportion of women who are married accelerating its long standing decline.

Since 2007, the United States has seen a sharp fall in its fertility rate. Looking specifically at the white population in the United States in 1940, during the Great Depression just after World War II started, the white Total Fertility Rate (TFR) was 2.229 children per woman. This rate then grew steadily reaching a peak in 1957 at the height of the Baby Boom with a white TFR of 3.625. After 1957 the fertility rate then fell steadily, plumbing the depths with a rate of 1.652 children per woman in 1976, the absolute low-point of white fertility up to this time. After 1976, white fertility slowly but persistently crept upwards reaching a high of 1.908 children per woman in 2007. In the three years since 2007, however, the white fertility rate has dropped sharply hitting a TFR of 1.791 in 2010; the lowest fertility rate since 1997.

In the past three years, from 2007 to 2010, the white TFR has fallen by 6%; for blacks it has fallen by 8% and for Hispanics it has fallen by an amazing 17%. In 2010 the Hispanic TFR rate was only 12% above replacement level. If the Total Fertility Rate among Hispanics falls as quickly from 2010 to 2012 as it did from 2008 to 2010 then in 2012 the Hispanic TFR will be 2.05, below replacement level.

There is a comparison to be made between the white TFR from 1965 to 1968 and the Hispanic TFR from 2007 to 2010. From 1965 to 1968, the white TFR dropped 15%, from 2.783 to 2.366. From 2007 to 2010, the Hispanic TFR dropped 17%, from 2.840 to 2.353. Has Hispanic fertility plunged since 2007 simply because of the economic crisis or might there be a deeper, feminist-inspired aversion to children that will ultimately place Hispanic fertility rates below the replacement level as well?

The periods from 1980 to 1994 and from 2003 to 2007 were characterized by rapid growth in the out-of-wedlock birth ratio. The periods from 1994 to 2003 and from 2007 to 2010 have been periods of risk aversion where the out-of-wedlock ratio has grown slowly. The first period of risk aversion, from 1994 to 2003, was characterized by a mild decline in the birth rate of unmarried women combined with a welcome increase in the birth rate of married women leading to a slower increase in fertility. The proportion of reproductive age women who were married fell more quickly during this period than before. The current period of risk aversion, starting in 2007 and continuing at least to 2010, has been characterized by a sharp drop in the fertility rate of both unmarried and married women and a sharp drop in fertility overall. The proportion of reproductive age women who were married has fallen more quickly during this current period than in the prior period of risk aversion.

So it seems clear that the current period of risk aversion is more severe than the prior period. In the prior period, overall fertility was maintained. There was a moderate retreat from marriage, and there was a shift away from unmarried women having children to married women having children. In the current period of risk aversion both unmarried and married women alike have reduced their fertility and the retreat from marriage has been more severe.

The first period of risk aversion was most likely due to a “cultural panic” where the problems of out-of-wedlock births were widely talked about, crime was out-of-control, and welfare reform was soon to be enacted. The current period of risk aversion seems to be caused by the current and ongoing economic crisis.

The below table, based on figures from the National Vital Statistics System, is an updated version of a prior table given in the “Fertility and Marriage Declines” post. I highly recommend this earlier article for those who want a more thorough and historical understanding of the history of out-of-wedlock births. The labels in the table are: %Ill. (Percent Illegitimate, the proportion of children born out-of-wedlock); UnMar. b/r (Unmarried birth rate, the number of children born to unmarried women per 1,000 unmarried women in the population of reproductive age; reproductive age being from 15 to 44 years old); Mar. b/r (Married birth rate, the number of children born to married women per 1,000 married women of reproductive age); %Mar (Percent Married, the proportion of women of reproductive age who are married); TFR (Total Fertility Rate, the number of children a woman can expect to have in her lifetime given current fertility rates)

(The below table comes from data given in government sources as well as my own calculations using data from government sources.)

Below is more detail on what has happened during the most recent period; from 2007 to 2009. The tables give the out-of-wedlock ratio for each race and each age group from 2007 to 2009. You will see that out-of-wedlock ratios have continued to rise across the board when broken down by age group. (White is non-Hispanic white, Black is all blacks, and Hispanic is all Hispanics)

Out-of-Wedlock Ratios by age group and race; 2007-2009

The below table shows that the proportion of total births has shifted away from women under 25 towards women over 25 from 2007 to 2010. Among whites, the proportion of total births to women under 25 decreased, increased for women 25 to 35 years old, and decreased for women 35 to 39. Among blacks, the proportion of births to teenagers 15 to 19 years old decreased while the proportion of births to women over 30 increased. Among Hispanics the proportion of births to women under 25 decreased while the proportion of births to women over 30 increased. This shift to women having children at older ages has helped to reduce the overall out-of-wedlock birth ratio since births to younger women are more likely to be out-of-wedlock than births to older women.

The below table gives the Total Fertility Rate and the proportion of total births to women in each age group by racial category for the years 2007 to 2010. (White is non-Hispanic white, Black is non-Hispanic black, and Hispanic is all Hispanics)

Total Fertility Rate and Age Distribution of Mother by race; 2007-2010

A blow-by-blow history of the white fertility rate in the United States since 1940 is offered below in a grid. “White” refers to all whites from 1940 to 1985 and to non-Hispanic whites from 1990 to 2010. To the left is the year and to the right of each year is the white TFR of that year. In Europe today, based on 2009 figures, every single country has a Total Fertility Rate (TFR) below replacement level, below 2.1 (excepting Iceland). There are several countries whose TFR was above 1.9; Ireland, France, Sweden, United Kingdom, and Norway. On the other hand there were even more countries whose TFR was below 1.4; Germany, Spain, Latvia, Hungary, Austria, Poland, Portugal, Romania, and Moldova.

History of the White Total Fertility Rate in the United States from 1940 to 2010

Replacement level fertility is considered to be 2.1 children per woman. A woman on average needs to have at least one daughter who can then have one daughter, etc. Since the sex ratio at birth is 1.05 males per 1 female the average woman needs to have at least 2.05 births in order to have the one daughter she needs to continue the population. I suppose the reason why 2.10 is considered replacement level is because some children will die before they reach 15 years old. The important thing is that on average each woman needs to have one daughter make it to her reproductive years so that she to can have one daughter, etc.

The “Total Fertility Rate,” the most commonly used measure of overall fertility, assumes that all women survive to the end of their reproductive years. How the Total Fertility Rate is calculated is by simply adding up the fertility rates at each individual age in a woman’s life and putting together a total. The fertility rates at each age are the number of births divided by the number of women of a particular age. All the women who died before reaching a particular age are not counted since they are no longer part of their original birth cohort.

The Wikipedia entry on “Demography” does a good job explaining where the “Replacement Level of Fertility” (RLF) comes from.

The more precise measure of whether a population is having enough children to sustain itself is the “Net Reproduction Rate.” If the Net Reproduction Rate is 1.00 then the population is sustaining itself with new births. If the Net Reproduction Rate is 2.00 then the population is doubling every generation while if the Net Reproduction Rate is 0.50 then the population is halving every generation.

Unfortunately, the Net Reproduction Rate (NRR) is no longer calculated every year in the United States; they apparently stopped calculating this measure annually in 1990. A report however was put together calculating this measure for 2000 and 2001.

Below is a table of the TFR and the NRR and RLF for the United States as a whole 1960 to 2001 (the updated overall 2001 TFR is 2.031):

The reason why Replacement Level Fertility has declined since 1960 is that fewer women are dying at young ages before their reproductive years are complete. A decreasing ratio of boys being born compared to girls will also reduce the Replacement Level of Fertility but I don’t think the sex ratio at birth has changed much in the United States since 1960. In countries like China with a strongly skewed sex ratio in favor of boys the low number of girls does indeed means that the ability to sustain the population is even worse than it appears when looking only at the Total Fertility Rate.

Finally, readers may be interested in a global map of Net Reproduction Rates. The map is based on 2010 data from the United Nations. If you put your mouse over individual countries it will give you the specific Net Reproduction Rate. This interactive map comes highly recommended.

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