New research led by Hyeokmoon Kweon and Philipp Koellinger at Vrije Universiteit Amsterdam shows that genetic luck contributes to inequalities between siblings in education, income and health. But the study also demonstrates that social and other environmental factors are the main drivers of variation in income and that the implications of specific genetic endowments are malleable, for example, via policies targeting education.
To measure genetic fortune, the study first scanned the genomes of more than 200,000 individuals from the UK for associations with income. Next, using an independent sample of approximately 35,000 UK siblings, the study constructs what is called a ‘polygenic score’ for individual income that summarises the effects of more than one million genetic markers to examine how random differences in the genetic score for income between siblings are related to different lifetime outcomes.
The results show that genetic luck for income contributes to inequalities between the siblings in the sample throughout the life course. The sibling who was by chance endowed with the higher genetic score for income tends to have more favourable outcomes throughout life, including a higher chance of obtaining a college degree and a well-paid job, of living in a good neighbourhood, and of being healthy.
Inequalities in society due to ‘luck’ or ‘fortune’ are often perceived as unfair and less desirable than inequalities that are considered to be down to hard work and perseverance.
Identifying and understanding inequalities of luck may encourage people to favour redistributive policies more strongly than they would have otherwise; this has potentially valuable policy implications. In environments where social inequalities are widening and are sources of polarisation, the unfairness of inequalities due to luck could serve a unifying purpose.
To explore how important luck is for how well people do in life, the new study sheds light on an important source of luck: the genetic lottery. Since parents pass down a random combination of their genes to their children, genetic differences among siblings are the outcome of a natural lottery. This genetic lottery is luck in the sense that no one has any influence on who their parents are or which genes they receive from them.
Using a large, genotyped sample of siblings from the UK, the study demonstrates that genetic luck contributes to inequalities between siblings in education, income, and health. But the study also demonstrates that social and other environmental factors are the main drivers of variation in income and that the implications of specific genetic endowments are malleable, for example, via policies targeting education.
Genes may be associated with lifetime outcomes for a variety of reasons. The same genetic variant might be positively associated with one specific outcome, but have no or even negative implications for another. In order to investigate the implications of the genetic lottery for inequality, the authors focus on the results of the genetic lottery for individual income because it is an important dimension of inequality that is of central importance for quality of life.
To measure genetic fortune, the study first scanned the genomes of more than 200,000 individuals from the UK for associations with income. Next, using an independent sample of approximately 35,000 UK siblings, the study constructs what is called a ‘polygenic score’ for individual income that summarises the effects of more than one million genetic markers to examine how random differences in the genetic score for income between siblings are related to different lifetime outcomes.
The results show that genetic luck for income contributes to inequalities between the siblings in the sample throughout the life course. The sibling who was by chance endowed with the higher genetic score for income tends to have more favourable outcomes throughout life, including a higher chance of obtaining a college degree and a well-paid job, of living in a good neighbourhood, and of being healthy.
But these inequalities due to genetic luck are malleable because the effects of the genes themselves are malleable. For example, the study shows that the effects of the genetic lottery for income partially work via educational attainment.
Since educational attainment depends on policies and other environmental factors, the study’s findings illustrate that the effects of the genetic lottery work via environmental pathways that can be changed.
Furthermore, the study argues that the role of genetic luck in producing inequalities across the lifetime can be used as a moral argument in favour of redistributive policies that emphasise greater solidarity in society.
Author affiliation:
Hyeokmoon Kweon, Casper Burik, Richard Karlsson Linnér, Aysu Okbay, Ronald de Vlaming, Philipp Koellinger: Vrije Universiteit Amsterdam, Economics
Daphne Martschenko: Stanford University, Center for Biomedical Ethics
Thomas DiPrete: Columbia University, Sociology
K. Paige Harden: University of Texas Austin, Psychology.
Contact:
Philipp Koellinger
E-mail: p.d.koellinger@vu.nl
Twitter: @PKoellinger