Concussions are prevalent in high-impact and much-beloved sports such as American and Australian football, rugby, and hockey. Concussions are harmful – recent studies link repeated concussions to degraded cognitive performance along a number of measures (Randolph et al. 2013), as well as an increased risk of neurodegenerative conditions such as chronic traumatic encephalopathy (McKee et al. 2013). Concussions are much in the news. Recent events such as the suicide of Dave Duerson and the suicide of Junior Seau have been linked to the long-term effects of repeated concussions, and the governing bodies of many high-impact sports have, of late, been scrambling to address the problems posed by growing awareness of the danger of concussions.

A number of ethical questions arise in connection with this growing awareness. (What should the governing bodies of sports leagues do to protect players? What do teams owe players in such sports? Is the decision to play such a sport, or to continue playing in spite of suffering a concussion, really autonomous? Should fans speak up about player protection, and if not, are they complicit in the harm done to players? And so on.) Here I want to consider one question that has received little attention. It involves the role of parents in fostering participation in high-impact sports.

Without parental encouragement, participation in such sports would dramatically decrease. Certainly, parental encouragement or discouragement can be trumped. In societies which highly value such sports, some adolescents would find a way to participate. But I will not consider here the (vexing) question of how best to respect an adolescent’s budding autonomy. Arguably, if an adolescent wants to participate in a high-impact sport, a parent should acquiesce. Whether that argument is plausible depends, in part, on the risks of playing the sport in question. The question I want to consider is the following: is it morally permissible for parents to encourage their children to play high-impact sports? (We might also consider the related question: ought parents to discourage their children from playing high-impact sports? I leave consideration of that for the reader.)

If behaviour is any guide, many think that it is permissible to encourage such participation. For participation in high-impact sports, in most Western nations, is celebrated. In the United States, an estimated 4.5 million youth between the ages of 6 and 18 play football. Hockey and Rugby remain popular all over the world. Participation in these sports is generally seen as a good – playing these sports enhances the development of character, provides access to valuable experiences, and positively impacts the well-being of participants. It is widely acknowledged that playing high-impact sports comes with a risk. Most of us, by now, are aware of the awful stories of adolescents dying on the field from injuries (according to the National Center for Sport Injury Research at the University of North Carolina, in U.S. high school football from 1993-2012 there were an average of 3.5 deaths per year, see here). But the general thought seems to be that the gains far outweigh the risks.

In my view the answer to our guiding question is not at all straightforward. If people judge it obviously permissible for parents to encourage such participation, this is due to (a) mistaken value-judgments, or (b) under-appreciation of the risks. I say something about the risks first. Then I turn to value-judgments.

First, an admission: because we lack full knowledge of the long-term effects of concussions and sub-concussive collisions on mental health and functioning, we lack full knowledge of the relevant risks. Because of this, it is easy to hide behind something like this reasoning. “Millions of adolescents play high-impact sports, and injuries are few. Therefore, risks are few.” But we know enough to regard this kind of reasoning with suspicion. Gilchrist et al. (2007) note that an estimated 22,689 football-related brain injuries leading to an emergency room visit occur each year in the United States. Strikingly, youth between 5 and 18 years old account for 90% of these events. Many concussions do not lead to emergency visits: Broglio et al. (2009) report that an estimated 43,000 to 67,000 high school football players are diagnosed with concussion per year – that represents 3.6% to 5.6% of the population of high school football players. Once concussed, athletes face larger risks: as Gilbert and Johnson (2011) note, such athletes “are four to six times more likely to experience a second concussion, even if the second blow is relatively mild, with an increased likelihood of catastrophic head injury following prior minor head injury” (49). This data is drawn, of course, from instances in which concussions have been diagnosed. But concussions often go undiagnosed, especially in youth football leagues where access to skilled physicians is much reduced compared to high-level college and professional football.

To make matters worse, concussions are not the only risk youth playing high-impact sports face. There is growing evidence that the effects of multiple sub-concussive collisions – basically, the kinds of hits that occur routinely in high-impact sports – are harmful, and that the harm accumulates over time. Consider a recent study by Talavage et al. (2010), in which researchers measured the impact of head collision events on a sample of 21 high school football players, utilizing sensors installed in the players’ helmets. Before, during and after the football season selected players were tested for neurocognitive functioning and neurophysiological signal changes (using functional magnetic resonance imaging).

The results are troubling. Four players were diagnosed with concussions during the season, and in-season testing revealed impaired neurocognitive performance. Eight non-diagnosed players were invited to participate in in-season testing, and of these eight, four showed significantly reduced neurocognitive performance, as well as decreased activation in dorsolateral prefrontal cortex and the cerebellum. Why would non-concussed players exhibit symptoms similar to concussed players? Evaluation of data from the sensors installed in these players’ helmets indicates that the negative symptoms correlate with a higher number of collision events overall. Talavage et al. speculate that “in addition to players that do not report their symptoms, the results presented here indicate that additional athletes . . . may be accruing damage that does not immediately result in symptoms that are typically observed by a clinician” (9).

If, as mounting evidence indicates, risk of harm to players increases with number of sub-concussive collision events, parents have reason to worry. Sub-concussive collision events are of course common in high school football. A recent study involving 95 high-school football players across four seasons found an average of 652 head impacts per player per season, with the number varying according to position (Broglio et al. 2011). But such events appear to be common for younger players as well. Daniel et al. (2012) found that 7- and 8-year-old players average over 100 events per season.

These studies are recent, and it should be noted that we have as yet no precise way of quantifying the risks to players from repeated sub-concussive collision events. But the risks go beyond the dramatic, and statistically unlikely, chance that repeated hits will trigger chronic traumatic encephalopathy. It looks like repeated concussions, as well as repeated sub-concussive collisions, negatively impact basic neurocognitive functioning. Both during and after the season many players are impaired on basic working memory tasks – and working memory is, of course, important for normal functioning on almost any task you can imagine.

So there are significant risks attached to playing high-impact sports. Why encourage participation? Broadly, two sorts of argument might be offered. First, one could argue that the positive features of sports in general outweigh the risks. Second, one could argue that the positive features of some high-impact sport in particular outweigh the risks.

The first type of argument is not convincing. If the positive features are those attached to sports in general, one should participate in a sport that is less risky. And indeed, one might get similar benefits – character development, social benefits, and so on – from participating in non-sporting activities. So the value-judgments behind this argument do not justify encouragement of participation in high-impact sports in particular.

The second type of argument depends on the details. In general, it is dubious that features of a high-impact sport qua the sport that it is are so positive as to justify participating in that sport and not some low-impact sport, or some non-sporting activity. But one might argue that participation in a high-impact sport is valuable not because of the sport that it is, but because of extrinsic features attached to participation. In the United States, for example, football is passionately beloved. Talent at football can earn one a college education, the esteem of one’s peers, and related socioeconomic benefits. The same is true of other high-impact sports in other countries.

Are the benefits worth the seemingly significant health risks? The risk-averse might have already heard enough to answer in the negative. But for those less risk averse, and more prone to valuing the socioeconomic benefits, the degree of risk might seem very important. Such parents might want to know more about the lasting impact of repeated sub-concussive collision events: something we do not know enough about at present. It is worth noting, however, that socioeconomic benefits are available to those who develop talents in other arenas. College educations, the respect of one’s peers, and satisfying careers are available to those who focus on music, or science, for example. Those who would emphasize the benefits attached to a particular high-impact sport must be careful not to let love of the sport in question crowd out the alternatives. Indeed, even given the significant practical benefits attached to participation in a sport society highly values, it is arguable that once we subtract love of the sport, the reasons for encouraging participation are weak.

Although the known risks seem to me significant, it is difficult to say with confidence that encouragement of participation in a high-impact sport is morally impermissible. I don’t claim to have made a knock-down case for that view. But I do think that parents face here a difficult choice – one much more difficult than is commonly acknowledged. Two upshots: parents have a reason to pay close attention to the emerging science of concussions, and scientists have reason to clearly communicate emerging results to the public.

Broglio, Steven P., et al. “Head impacts during high school football: a biomechanical assessment.” Journal of athletic training 44.4 (2009): 342.

Broglio, Steven P., et al. “Cumulative head impact burden in high school football.” Journal of neurotrauma 28.10 (2011): 2069-2078.

Daniel, Ray W., Steven Rowson, and Stefan M. Duma. “Head impact exposure in youth football.” Annals of biomedical engineering 40.4 (2012): 976-981.

Gilbert, Frédéric, and L. Syd M. Johnson. “The impact of American tackle football-related concussion in youth athletes.” AJOB Neuroscience 2.4 (2011): 48-59.

Gilchrist, J., et al. “Nonfatal traumatic brain injuries from sports and recreation activities-United States, 2001-2005.” Morbidity and Mortality Weekly Report 56.29 (2007): 733-737.

McKee, Ann C., et al. “The spectrum of disease in chronic traumatic encephalopathy.” Brain 136.1 (2013): 43-64.

Randolph, Christopher, Stella Karantzoulis, and Kevin Guskiewicz. “Prevalence and characterization of mild cognitive impairment in retired national football league players.” Journal of the International Neuropsychological Society 19.08 (2013): 873-880.

Talavage, Thomas M., et al. “Functionally-detected cognitive impairment in high school football players without clinically-diagnosed concussion.” Journal of neurotrauma (2010).