Leonardo da Vinci was one, as was Frank Sinatra. One-child families are on the increase in the UK and the fastest growing family unit in western Europe. BBC presenter Julian Worricker - himself an only child - looks at life without siblings.
I am an only child and I consider myself to be one who bucks the trend, in that I hope I don't match some of the rather tired stereotypes on the subject.
There's a negative view that only children are pampered too much and are therefore reluctant to take on responsibility as adults. I prefer the more positive view that we are better at making friends and generally more adaptable.
The subject of only children appeals to me professionally as well. Last year I was lucky enough to spend two weeks in China for work and the effects of its one-child policy were never far from my mind.
I remember chatting to colleagues after a day at a very impressive school in Shanghai. What was China going to be like in 20 years we wondered when all those focussed, driven, sibling-free pupils, in whose futures parents were investing so much time and energy, were running the place.
China: a one-child policy since 1979
Here in the UK, we're looking at a situation where only children are becoming ever more commonplace. Couples are starting families later and once they've started they increasingly stop at one.
In the UK there were 300,000 more households with one child last year than there were in 2000. It's a trend echoed in Germany, Spain and Portugal.
One is enough
Being an only child is not something I've given a great deal of thought to over the years. It wasn't by design; suffice to say I took longer to arrive than was originally planned and no siblings followed.
My childhood was a very happy one; there were cousins to share family holidays with and friends at school who all seemed to be terribly jealous of the fact that I didn't have any brothers or sisters. Most of them were always falling out with theirs, so my situation seemed very appealing.
Of course my lack of siblings meant there were times spent alone, or away from other children at least. But I don't remember that being a negative thing. I quite enjoyed my own company, within reason - a fact that remains true today.
No need to share toys
And let's face it, if I went to school in the morning and left my toys in a certain place for a very good reason, they were always where I left them when I got home.
As I got older I didn't go through a significant teenage rebellion phase. There was the occasional sulk or disagreement, but nothing to send my parents diving for cover.
I'd never really given this much thought until an author of a book about only children said this seemed to be true of a lot of us.
It's dangerous to indulge in too much amateur psychoanalysis in these situations, but various theories have been put forward; we enjoyed a more adult relationship with our parents at an earlier age and therefore didn't rebel, or maybe we didn't have a sibling to vie with in the rebellion stakes.
The same author said it was also true that some only children were simply postponing their teenage rebellion until well into adulthood. So here I am at the age of 43 rather invigorated by the prospect of being thoroughly awkward at some point in the next few years.
So when we reach adulthood, is it obvious that we have no siblings? What, if anything, are we doing, saying, thinking, that marks us out, that acts as a common thread despite our individual upbringings? Several studies have been conducted on the subject.
One broad-based study conducted on college students in the United States in the 70s suggested that, apart from slightly higher academic achievement coupled with a greater feeling of self-esteem, there was no significant difference in growing up as an only.
In China, where the one-child policy has been in place since 1979, various studies have been carried out. Most point to minor differences between only children and those with siblings.
As an adult I still have a pretty positive view of being an only child, but it's also true to say some doubts have entered my mind.
I'm lucky enough to have both my parents fit and well as they approach their 80s, but when there are doubts or worries about them there's no sibling to phone who will share them.
However close my friends are, it's not the same as being able to refer to "mum" or "dad", safe in the knowledge that they belong to someone else too.
But in the end, the experience of being an only child is different for each person. While there is common ground, experiences vary and some of us simply enjoy it more than others.
I wouldn't suggest that only children are better or worse than people with brothers and sisters; they're simply different.
The One And Only will be broadcast on BBC Radio 4 on Monday, 8 May at 1100 BST.
Send in your comments using the form below.
Not only do we "onlys" have no sibling to share responsibility for aging parents, if we partner another only (increasingly likely as the number of us goes up), then our child will have no uncles, aunts or cousins, so the effect of shrinking families is magnified down the generations.
I felt guilty that my daughter was an only child until she started to study French at school and learned the French for an only child is "une enfante unique". She said this made her feel special.
Val, Stockport, UK
There is tremendous pressure on my conscience to succeed as the parent of an only child. My husband and I face the constant battle of are we spoiling her, or being too hard on her. We can afford to lavish presents on her (we don't) but what kind of adult will that make her in later life? She rarely has to share toys but perhaps more importantly she doesn't have the opportunity for healthy everyday squabbles and arguments - how will she fare when she has to stand up for herself in an argument? She seems more independent than most children her age, she is happy with her own company, but we feel that she does miss out on the freedom that she might have had with siblings - going to the shops together, going to play in the woods/fields. The life of an only child can be hard, but the right or wrong decisions her parents make are crucial to her success in later life.
Sarah Thomas-Burton, St Albans
It does not matter whether you have one child or 11, it is the parents' love (or not) and (un)willingness to put in all the time and hard work to guide and discipline their children which determines whether or not a person grows up in an honest, decent, self-disciplined and useful member of society.
Cat Stewart, Derbyshire
I'm one of three and we scrapped like cats and dogs as children. Very unpleasant for parents and children alike. In adulthood we're friends but not close. Ditto my partner. We consciously decided on one child (for many reasons) but the fighting over resources, parental attention etc is largely circumvented. Amen to that!
I've a lovely 20-month-old and the question "so, when's number two?" crops up with increasing frequency; but we're pretty certain we only want the one child - for financial reasons, for space, for enjoying our mostly-charming toddler, and because twins run on both sides of my family... one more child? Maybe. Two more? Cripes! But why do we feel we have to justify this decision anyway?
I am one of five children and would hate to be an only child for the simple reason that a brother/sister relationship is unique and no matter how close you are to friends or family, it's never the same thing. You always have your sisters and brothers to celebrate and cry with, and nobody knows or understands you in quite the same way. And Christmas wouldn't be the same without a houseful of us.
I was an only child simply because my father died when I was only three and although my mother married again there were no more children. I make friends easily so was not lonely and I find a lot of truth in the saying "You can choose your friends but are stuck with your relatives". Many of my friends do not get on with their siblings and value my friendship more.
Gillian Giblin, Richmond, Surrey
I feel that the self-sufficiency inherent in being an "only" helped me through turbulent times, when there was no sibling to share the brunt of my controlling mother's resentment and jealousy. It was a burden to be borne alone, yet prepared me for later life, having to struggle through similar vicissitudes. I believe that sense of "going-it-alone" has spurred me on, has enabled me to experience positive things, such as travelling abroad alone by car, without the need for the approval of others. It's not all joy, but there are definite emotional advantages.
Molly Ayre, Halton, Cheshire
I am an only and believe is has been a contributing factor to who I have become. Outgoing, confident not risk adverse, but comfortable with the management of risk. I have, I feel, had my rebellious elder period which has led to divorce, remarriage and a far happier outcome.
Kevin Turner, London
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