The Science of Siblings: Health Benefits?



The photo above shows our lavender plants in bud along the garden path. We refer collectively to our two youngest children as the Darling Buds of May. Nothing to do with the old BBC TV show of that name, but because the Buds (as they’re known for short) were both born in May (albeit 4 years apart).

When we invented the collective nouns it was allegedly to save time. But really it’s as much a bit of fun.  The eldest two are the Pre-Raphaelites, since they were born ahead of Raphael.  The middle two are the Dorset Darlings, since they share a birth county and a rather dear disposition.  I’m not sure if the oldest and youngest have a collective noun as yet, although one is the spit of the other.  So perhaps the Spits?

In his book, Sticking Up For Siblings, Colin Brazier outlines a variety of ways that siblings can benefit one another and society in general.  One which he explores in some depth is the health benefits which sibship seems to bring.  He looks at the evidence that germ-swapping builds stronger immune systems, with sliding-scale reductions in the odds of younger siblings developing eczema, asthma or food allergies.

He also takes an entire chapter to consider the fairly persuasive evidence that siblings, or lack of them, play an influential role in obesity levels.  I expect this is news to you; it certainly was to me.  But it’s worth a moment’s thought.

“A 2009 study from University College London noted that ‘smaller family size [was] associated with higher childhood BMI (body mass index)’. These 21st century studies offered fresh statistical impetus to a solid base of research from previous decades. A massive 1977 data sweep of all the children born in Newcastle-upon-Tyne found that ‘being an only child’ was one of the ‘most significant’ causes of obesity in children. A year later came the great-grand-daddy of them all. It was a piece of research explicitly seeking a link between sibship size and obesity. They examined data from 280,000 19-year-old Dutch males, born between 1944 and 1947. The authors rounded-off their report with these words: ‘Individuals from one-child families (only children) were uniquely at risk for obesity, particularly in the non-manual social class.”

Whilst Brazier reckons that energetic play is the main cause of his 6 kids’ svelte figures, I propose the reason our kids aren’t overweight is that there’s simply not enough food to support that scenario. I can easily cook enough for one child to routinely overeat, but if you want me to provide oversized portions for four of them then you will have to double my food budget, and provide me with larger pans. (Actually I already have the pans, since I recently invested in larger ones, but that was to bring to an end the terror of food always slopping over the sides of our old pans – the ones that used to be big, but over the years have gradually shrunk.)

Indeed, Brazier observes that:

“Excepting thyroid problems and other inherited causes, obesity has two main determinants. First, calorific input is too high. Second, energy expenditure is too low.”

Calorific input is often the result, apparently, of too much doting, and that (according to statistics drawn from the British Milliennium Cohort Study of 12,000 3-year-olds) often by the Grandparents! (Father dear, take note: all those ice-cream puddings are potentially making our children 15% more obese.) Apparently China’s one-child policy is credited, amongst other things, with some responsibility for the country’s sharp rise in obesity, while parents and grandparents dote on their little emperors.

Clearly the existence and/or number of siblings does not define a child’s BMI.  My points are, as ever, tongue-in-cheek, and Brazier’s are careful to include, for example, the increase in availability of fast-food, and the protective styles of parenting which mean kids don’t seem to walk anywhere anymore.  For many children, however, it may register in the deciding factors, as children with siblings are very often calorifically-less-indulged (yep, that is now a thing), and they are more likely to use up their calories rushing around together like headless chickens from game to game, on a daily basis.

“Whatever the reason, the statistical corpus is vivid,” declares Brazier, before offering the wonderful and memorable maxim that, “As families grow, waistlines shrink, all other things being equal.”

Purchase Sticking Up For Siblings or download it from Civitas for free.

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