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So your parents want you to be a doctor?

Dec 16 2020
Petra Persson and Maria Polyakova

SIEPR faculty fellows Petra Persson (left) and Maria Polyakova, examine heritability of the medical profession in a new study published by the British Medical Journal.

 

Photo by holly hernandez
Learning about an occupation from Mom or Dad has a long tradition — and has led to scientific and economic advances. Irene Curie joined her mother Marie in becoming a pioneer of nuclear medicine — and Nobel Prize winner. Sons have become U.S. president after their fathers. The notion of carrying the family career torch is even the stuff of Hollywood heroics, as “Star Wars” fans will recall Luke Skywalker proclaiming: “I am a Jedi, like my father before me.”
 
Can this concentration of expertise within families have any unintended consequences? 
 
Increasingly, a concern is arising that high barriers to entry into the most lucrative occupations, combined with transmission of knowledge within families, may perpetuate socioeconomic inequalities by creating occupational dynasties.
 
In a new study published Dec. 16 in the peer-reviewed British Medical Journal, Stanford assistant professors  Petra Persson and Maria Polyakova examine heritability of the medical profession, which is among the highest-paying jobs in many countries. 
 
Using administrative data from Sweden, they show that the medical profession is becoming increasingly concentrated with doctors who are the offspring of physicians. Among doctors born in the 1980s, 1 in 5 had a parent who practiced medicine. That’s triple the number for those born in the 1950s.
 
The results are significant, the researchers say, because in addition to the general concern about equality of economic opportunity, socio-economic diversity in medicine may be important for improving patients’ health.  
 
“Research has shown that patients who can closer identify with their doctors in terms of cultural or socioeconomic background are more likely to follow medical advice and to have better outcomes,” Polyakova says.
 
The evidence is particularly striking because Sweden is considered one of the world’s most equitable societies where many of the suspected barriers to entering the medical profession don’t exist, Persson says. For example, Sweden provides free medical education.
 
“We might have hoped to see medicine in Sweden become more diverse over time,” Persson says. “Instead, we find that a highly selective profession is becoming even more selective.”
 
If Sweden has this problem of few doctors coming from outside of physician dynasties, Persson and Polyakova say, it’s reasonable to speculate that other countries do as well.
 
A dramatic change over 30 years
 
Polyakova and Persson — both faculty fellows at the Stanford Institute for Economic Policy Research (SIEPR) — have worked together on issues around health inequality and, in particular, on the question of whether differences in access to information and expertise can contribute to differences in health outcomes across households living in different socioeconomic circumstances. 
 
For example, in a 2019 working paper that also relied on data from Sweden, they found that people with a relative who was a doctor or nurse — and hence who had informal access to expert knowledge — lead healthier lives. The positive health effects were often strongest among lower-income households.
 
Their new study — co-authored by Katja Hofmann, a Stanford doctoral student in economics, and Anupam Jena of Harvard Medical School — affirms extensive research in the United States and elsewhere showing that socioeconomic status is hereditary and getting stronger over time. Children who grow up in poor households are likely to work low-wage jobs as adults. Adult kids of high-income parents typically have higher incomes themselves.
 
Whether this intergenerational persistence of incomes operates through sons and daughters pursuing the same careers as their parents, a concept known as “occupational heritability,” is not entirely clear. A few studies, for example, have established that children of entrepreneurs and inventors tend as adults to start their own businesses and dream up new creations. Often, however, the necessary data are hard to come by. 
 
“We had the advantage of fantastic administrative data that allowed us to connect several generations of individuals and to track their occupations and economic circumstances,” Persson says. “This was a unique dataset.”
 
Their analysis showed that, among physicians born between 1950 and 1959, 6 percent had a parent who was also a physician. For the 1980-1990 birth group, that number reached 20 percent — or just over three times as many. They also looked at the proportion of physicians with aunts, uncles and grandparents who were also medical doctors and found that, except for siblings, those numbers also increased.
 
Like mother, like daughter — but not for lawyers
 
To find out if the results were specific to physicians — or simply more evidence that people are likely to inherit their socioeconomic status captured by occupation — Polyakova and Persson also applied their analysis to lawyers. They found that, on average, 7 percent of lawyers in Sweden who were born either in 1950 or 1990 followed in a parent’s footsteps. 
 
If occupational dynasties aren’t getting stronger in the legal profession, something specific must be happening in the medical field, say Persson and Polyakova. They also say more research is needed to find out what’s causing the growing concentration of doctors with at least one parent in the profession. 
 
One possibility, they say, is that offspring of physicians have access to better information, which helps them determine at an earlier age that they want to become doctors. And as medical school has become more competitive, they could be more aware of the importance of top grades and also be more willing to persist through the application process.
 
“At this point, we can only speculate,” Polyakova says. But it’s important, she says, to consider the policy implications. “For example, our findings  suggest that one policy that is often discussed — making medical education free, like it is in Sweden, to attract applicants from underrepresented groups — may not really be an effective policy instrument.  Instead, it could be that better career counseling and exposure to role models at younger ages are far more important.”
 
Petra Persson is a faculty member in the School of Humanities and Sciences at Stanford. Maria Polyakova teaches in the School of Medicine and is a core faculty member of Stanford Health Policy
 
Krysten Crawford is a freelance writer.
 

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