WHAT do Leonardo da Vinci, Isaac Newton and Elvis Presley have in common? Apart from the fact that they were all innovators, they were also only children.

Academics at Southwest University in Chongqing, China recently published their research into people with no siblings. Their MRI study reports that the brains of only children are structurally different to individuals with one or more sibling and that singleton children are essentially less agreeable and more selfish. On the plus side, they claim that only children tend to be more creative and more aware of parental expectations (which may, in turn, influence the child’s cognitive performance and function). The study concludes that while undiluted parental attention is good for an only child’s creativity, it can also cause undesirable character traits, such as dependency, selfishness and social ineptitude (these researchers don’t mince their words).

I grew up in an environment where large, "just managing" families were the norm and where material wealth was paper-thin on the ground. Rarely was an item of clothing brand new to its wearer, unless, of course, you happened to be the first-born. Otherwise, coats, dresses, shoes and even vests, were handed down the sibling chain until, finally, taking on the aura of an ancient religious relic, they were no longer fit for purpose.

During the long summer holidays, we ran around feral, mostly in packs and nobody went abroad. The best you could hope for was a day-trip to Oban or Millport, and the crowning glory of a day spent running daft around the beach, was a sit-in fish tea with two giant pickled onions (per child).

We were chucked out of the house "to play" at around 9am, only to return briefly for refuelling at lunch and/or tea-time, then out again until the sun began to sink. Miraculously, the weather was always clement.

Within our small, 1960s-built council estate, there were three only children. These kids were regarded by the rest of us with a confused mixture of envy, awe and pity. Envy because they had better toys, newer and nicer clothes, a tidy room with dolls (or trucks or action men) displayed on tidy shelves that their dad made specially for them. One girl even had a bookshelf with proper books that had no torn or graffitied pages.

These only children lived in a world where their property and privacy were respected, their toys unbroken, their Monopoly and KerPlunk, intact and fully operational. In their solo-child world, they could leave a packet of Rowntree’s fruit gums on their bedside table when they went to school in the morning, safe in the knowledge that each sweet would be present and accounted for on their return home at 4 o’clock. No need to hide them in weird, sibling-resistant places.

My memory of those only children is that two of them were moody and unpredictable and, at times, rather sadistic and unkind to me. The other little girl was a delight. Generous, empathic and a bit timid, she shared her toys, felt sad if you felt sad and would gladly, lovingly give you her last sweetie. Looking back, I realise now that what differentiated the two self-centred kids from the really sweet one, was their parents.

The two spoilt kids had the sort of parents who seemed to take pleasure in telling you that you weren't allowed into their house to play, or, on the rare occasion that you did get in, would tell you to get out in 20 minutes (but first, you had to take your shoes off at the door). They discouraged their only child from sharing their toys, fearful the marauders might break them or, God forbid, steal them. It was as if the intrusion of other children into their home could somehow mess things up, turn the established order on its head.

In contrast, the parents, especially the mother, of the sweet little girl, were welcoming, respectful and genuinely interested in the other kids. Their expectations were not that their only offspring should outshine others with dazzling creativity or natural poise, but more that their child should be kind and empathic to others – especially to children who had to make do with much less. Their door was always open.

It is interesting that this recent study was conducted in China, where, until relatively recently, there was a one-child per family policy. Perhaps if all prospective parents knew they had one chance – and one chance only – to get it "right", to propagate their family’s lineage and unique genetic code, they would all be susceptible to seeing their child as very special, highly specialised. Such expectations can be onerous for the only child, even if it does confer certain advantages and opportunities.

In fact, all children are special and all children – whether we are one of four or one of one – are our shared future.