Experts in reproduction at Rigshospitalet are unequivocal: Human reproduction is in crisis.
The research team at the Department of Growth and Reproduction has dedicated their careers to investigating the biological causes behind declining fertility rates, increasing infertility, and issues with sperm quality. Their work on reproductive problems and environmental factors has gained international recognition through numerous publications in leading scientific journals since the 1990s.
Biological explanations, along with cultural and social factors, can offer insights into why fertility rates have declined over time in all industrialized countries.
»Everyone should have seen the writing on the wall decades ago«, says Professor Niels Erik Skakkebæk, who has spent decades researching male reproductive abilities and declining sperm quality.
»But the drop in fertility is likely not solely due to biology. The most concerning part is that we still don’t know the reasons. Without that knowledge, governments can do very little.«
The research group is now advocating for Denmark, due to its robust registries, to become the center of a multidisciplinary investigation into the fertility crisis, broadly examining the issue.
They believe there is less cause for concern if a thorough investigation reveals that the primary reasons for low birth rates are socio-economic factors, meaning social and cultural explanations.
»That can often be changed«, points out Anna-Maria Andersson, the research leader at Rigshospitalet.
»However, we face a much larger problem if low fertility and human reproduction issues are predominantly due to environmental influences that have made younger generations less fertile, possibly even infertile«, she says.
More than one in ten Danish children are born via fertility treatment.
Immigrants will dominate
To maintain a stable population, each woman needs to have an average of 2.1 children. This has not happened since the mid-1960s in Denmark, before abortion became freely available.
Denmark’s population isn’t declining yet – we now have 6 million citizens – but this isn’t due to Danes having many children. Rather, increasing life expectancy and immigration have compensated for the lower birth rates.
Rune Lindahl-Jacobsen, a professor of epidemiology and demography at the University of Southern Denmark, has projected for Politiken that by 2096, immigrants and their descendants will outnumber citizens of Danish origin in Denmark if current trends of low fertility rates and high immigration continue.
He points out that there are many explanations. For example, it becomes increasingly difficult for a woman to conceive and carry a pregnancy to term as she gets older.
The average age of first-time mothers has increased by seven years since the 1960s, so women today have their first child around the age of 30.
However, it is far from certain that the current decline in fertility is due to difficulty in having children, emphasizes Peter Fallesen, a research professor at the Rockwool Foundation who studies family demography.
»All evidence suggests that this is not the case. Fertility doctors have often talked about declining sperm quality as a cause. But sperm quality has not worsened since the 1990s, and the incidence of testicular cancer hasn’t deteriorated either. Quite recently – in 2008 – we had a high birth rate of 1.9 children per woman before it dropped again. So these biological reasons cannot explain the trend«, says Peter Fallesen.
»Fertility doctors have become incredibly skilled in recent decades, so most couples who want children and actively try do end up having them«, he says.
Education, money, and men
One of the most crucial points to understand about the current low fertility rates, according to the research professor, is this: People who have children are having the same number of children as before.
The decline in fertility is because there are significantly more people today who are not having any children. This is particularly true for women with shorter educations, notes Peter Fallesen.
For women whose highest level of education is primary school, fertility has more than halved since the financial crisis. There has also been a significant drop in fertility among women whose highest education is secondary school.
Among women with higher education, there is only a very small decline over the same period.
Much evidence suggests that many less-educated women choose not to have children for economic reasons, explains Peter Fallesen.
»After the financial crisis, the wage growth for less-educated individuals did not keep up with the rest of society. They have also found it harder to secure jobs. Thus, they are economically worse off. And even in Denmark, children aren’t free. They require space. If you don’t have enough money, it’s difficult to move to a larger home«, says Peter Fallesen.
Additionally, less-educated individuals are more often single.
»So they simply have a harder time finding someone to have children with.«
Less-educated women are therefore responsible for one of the most significant changes in how Danes have children.
While men with shorter educations have always had fewer children, it used to be that less-educated women had the most children. This has now changed, so today it applies to women with the longest educations.
Simultaneously, it has generally become more challenging to find someone you want to have children with, as recent research highlighted by Politiken last year showed.
Historically, women have tended to have children with men who had longer educations and higher wages than themselves. This has partially changed in recent years.
As women have surpassed men in higher education, women are increasingly having children with men who have shorter educations than themselves.
However, in almost all couples, the man still earns more than the woman – and this tendency is much more pronounced than can be explained by the general wage gap between men and women.
It seems that women are avoiding men with lower incomes, or men are avoiding women with higher incomes, or both. Whether this happens consciously or subconsciously, it means that more people will find it harder to find a partner as more women earn higher salaries, simply because there will be fewer men who earn more than women.
Given the explanations for the decline in fertility, it could become extremely challenging for politicians who want higher birth rates, Peter Fallesen assesses:
»In Denmark, we’ve already implemented the measures that effectively raise fertility. We already have childcare institutions, long parental leave, and more. Much of the decline in fertility is because more people, for various reasons, simply aren’t interested in having children. And all evidence shows that it’s really tough to get people to start having children if they don’t want them.«
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