We are looking at a childless future.
All industrialized countries are having fewer children. Not enough growth to maintain our current population size. With the exception of Africa, and certain small ethnic and religious communities, Total Fertility Rate—the number of children an average woman will have in her lifetime—is declining sharply. Government incentives cannot reverse this slide into a childless future.
Are we becoming less efficient at making babies?
In 1992, following a study by the Danish Elizabeth Carlsen showing worldwide decline by 50 percent in sperm density, there was a backlash of critical reports refuting these findings. Then in 1997 Shanna Swan and her colleagues from California Department of Health Services, performed a reanalysis of data from 61 studies. Their study supports a significant decline in sperm density since the 1950s in the United States and Europe. Although there are exceptions—and recent studies by Elizabeth Carlsen herself in 2012 has shown improvement in sperm count—there is still a large proportion of people who are compromised fertility. As an example, Denmark, during 2002–2004 reported more than one in fifteen Danish children born with assisted reproduction and, in addition, many couples were adopting foreign children.
The decline in sperm involves numerous factors, but the finger is pointing towards the use of pesticides and hormones in our food chain. Such an interpretation is supported by the increasing occurrences of testicular cancer and possibly also of malformations of the genital tract.
On the other side of the spectrum is the ability and motivation of women to have children. Women are having children later in life and when they have two or more children they are delaying each birth. Education—both formal and informal—plays a role in determining that women don't get pregnant early and then have children in quick succession. There is also a declining ability of women to have children, known as fecundity—the capacity to bear children. Women are experiencing increasing problems with conceiving and maintaining pregnancies.
According to the National Survey of Family Growth, one in seven U.S. women reported impaired fecundity in 2002. However, across a lifetime, Arthur Greil, from Alfred University, New York, and his colleagues, reported that more than half of women aged 25 to 45 in 2011 reported an episode of infertility at some point in their lives.
Although women are starting families later in life, which by itself reduces their success rate, there is an additional worry about declining fecundity. The Dutch researcher Boukje Zaadstra and her colleagues reported in 1993 that increasing obesity, specifically the waist-hip ratio, reduces the chances of conception more then age or overall obesity. So certain type of fat—stomach fat—effectively reduces fecundity among women. With an obesity epidemic reaching to all countries in the world, this has negative reproductive consequences. And it is the lower waist/hip ratio (WHR) rather than despite increasing BMI. Compared to women with high WHR, women with a low WHR have fewer irregular menstrual cycles (Van Hooff et al., 2000), optimal sex hormone profiles (Jasienska, Ziomkiewicz, Ellison, Lipson, & Thune, 2004), ovulate more frequently (Moran et al., 1999), and have lower endocervical pH, which favors sperm penetration (Jenkins, Brook, Sargeant, & Cooke, 1995). Low WHR is also an independent predictor of pregnancy in women attending an artificial insemination clinic (Zaadstra et al., 1993) and in women attempting in vitro embryo fertilization transfer (Waas, Waldenstrom, Rossner, & Hellberg, 1997).
Paul Ehrlich’s 1968 sensational book “The Population Bomb” was such a good work of fiction that programs to limit fertility were put in place worldwide. There are so many emperors without clothes nowadays that we are virtually a nudist colony.
© USA Copyrighted 2014 Mario D. Garrett
© USA Copyrighted 2014 Mario D. Garrett