When my youngest was about eighteen months old, our neighbour’s retriever wandered into our garden and sat very calmly next to him while he ate a biscuit. My son, who at that point screamed at the vacuum cleaner, did not flinch. He just kept eating and occasionally patted the dog on the head. I remember thinking: there is something happening here that I do not fully understand.
I had always thought of pets as nice for children in the way that playgrounds are nice. Enjoyable. Good for burning off energy. Emotionally uncomplicated. What the research over the past two decades shows is something quite different, and it is the kind of different that I wish someone had told me when I was trying to decide whether to get a cat.
The Immune System Connection
For most of the twentieth century, the medical consensus was that children should be kept away from allergens, and pets were squarely in that category. Fur, dander, saliva: all presumed threats. The problem with this thinking was that the data kept pointing in the opposite direction.
In 2002, a landmark study published in the Journal of the American Medical Association followed almost five hundred children from birth to age six or seven. Children who had been exposed to two or more dogs or cats during their first year of life were significantly less likely to develop common allergic sensitivities, including dust mites, ragweed, and grass, compared to children raised without pets. Not slightly less likely. Measurably, significantly less likely.
Children exposed to two or more pets in their first year of life were roughly half as likely to develop multiple common allergens by age six or seven, according to the 2002 JAMA study by Ownby and colleagues.
This finding sits within a larger framework researchers call the hygiene hypothesis: the idea that the immune system, especially in early childhood, needs exposure to a variety of microorganisms in order to calibrate correctly. A child raised in a sterile environment does not develop a stronger immune system. It develops one that has never learned what to ignore, and so it reacts to things that pose no real threat. Pets, with their outdoor microbiomes, their paws and fur and tendency to lick faces, are extraordinary sources of microbial variety.
The effect appears to be strongest in the first twelve months of life, which is when the immune system is doing much of its foundational calibration. After that window, exposure still helps, but the magnitude of the benefit is smaller. This is not a reason to panic if you do not have a pet yet. It is a reason to stop assuming that keeping animals away from babies is the cautious choice.
What Happens to Stress When a Dog Is in the Room
The emotional regulation research tells a different story, one that is less about biology and more about what children learn when they have an animal to care for and to sit next to during a hard day.
A consistent finding across multiple studies is that the presence of a pet dog specifically reduces cortisol levels in children under stress. Cortisol is the primary stress hormone, and chronically elevated levels in childhood are associated with a range of long-term problems, from anxiety to difficulties in social relationships. Children who had access to a dog during a stressful task showed lower cortisol responses than children who completed the same task alone, or even with a parent or friend present.
In controlled studies, children completing stressful cognitive tasks showed measurably lower cortisol levels when a dog was present in the room, compared to the same task completed with a parent or a supportive friend nearby.
The dog’s presence appears to offer something that human support, for all its value, does not: unconditional non-judgmental companionship at the exact moment it is needed. The child does not have to manage the relationship. They do not have to perform or explain or worry about the dog’s reaction. The dog simply stays. And something in that staying is measurably useful to the nervous system.
Gail Melson, whose work in Why the Wild Things Are covers decades of research on children’s relationships with animals, argues that we have consistently underestimated what these relationships do developmentally. Animals, she points out, occupy a unique category in a child’s world: they are living beings who do not speak, who respond to care, who have needs of their own, and whose wellbeing depends, at least in part, on what the child does. That is an unusually rich developmental environment.
Empathy, Responsibility, and the Things a Pet Teaches Without Trying
There is a reason that animal-assisted therapy has become a well-established intervention in children’s hospitals, schools working with children who have experienced trauma, and programmes supporting children with autism spectrum conditions. The research behind it points to something consistent: children who regularly interact with animals show higher scores on measures of empathy and perspective-taking than children who do not.
This is not magic. It is practice. A child who notices that the dog is anxious during a thunderstorm, who learns to read body language that has no words, who understands that a creature in their care can feel fear and can feel comfort, is doing the same cognitive and emotional work that underlies human empathy. They are practising the skill of reading another being’s internal state from external signals. The fact that the other being is a dog rather than another child does not make that practice less real.
Children who grow up with pets consistently score higher on measures of empathy and perspective-taking. Researchers link this to the daily practice of reading an animal’s non-verbal emotional signals and responding to its needs.
What we perhaps overlook is the responsibility dimension. A child who feeds a pet, who learns that forgetting has consequences for another living thing, who sees that care produces visible wellbeing, is learning something about cause and effect that no worksheet replicates. They are learning it in the most direct way available: through a relationship that responds.
What This Means in Practice
I am not saying every family needs a dog. I am aware of allergies, of rental restrictions, of time and energy and the sheer logistics of another living thing that needs feeding twice a day and walking in the rain. Lagom applies here too: the right amount is the amount your family can actually sustain without resentment.
But I do think it is worth setting aside the idea that pets are a luxury addition to childhood, something nice to have if circumstances allow. The evidence positions them closer to a developmental resource, one that trains the immune system, buffers the stress response, and builds the specific emotional skills we spend enormous energy trying to teach in other ways. A child who grows up with an animal has been practising things we care about, without either of them realising it.
Richard Louv, in Last Child in the Woods, makes a broader version of this argument about children’s contact with living things in general. The less time children spend in direct relationship with non-human life, he suggests, the more we lose something we cannot easily name or replace. Pets are, for most urban families, the most accessible form of that contact. Which is perhaps why the research keeps finding that they matter more than we expected.
Parenting is the longest experiment any of us will ever run. I am still reading the results.
Lila Sjoberg
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