By Vivienne Parry
Presenter, Am I Normal?
When it comes to your health, who decides what's normal?
Little: Sarah Teather
And is normal for Norwich, the same as normal for Norwood or come to that, normal for Norway?
If medical tests show that you're not normal, is that a reason to medicate and treat or a reason to celebrate your individuality?
The BBC Radio 4 series Am I normal examines these questions for some very different aspects of health, height, weight, heart and mind.
We can work out whether our height is normal simply by standing in a queue for the bus.
In Britain, the average height is 5' 4" (1.63m) for women and 5' 9" (1.75m) for men.
Daniel Kawczynski is Britain's tallest MP.
"Officially I'm not normal, because anyone over 6' 8" (2.03m) is classified as a giant and I'm 6' 9" (2.06m).
In contrast, Britain's shortest MP is Sarah Teather: "I'm 4' 10" (1.47m) - on a good day, with big hair."
Does she think of herself as normal? "I'm an MP, I can't be that normal," jokes Teather.
But resoundingly both see their departure from normality as a reason to celebrate.
And large: Daniel Kawczynski
"We're memorable, people know me when I walk down the street," says Daniel.
But would it still be normal if Sarah was the one that was 6' 9"?
Whilst very tall men are not considered in need of treatment, it's a different matter for the very short, particularly boys.
"There is lots of evidence that shorter people are disadvantaged," claims child growth specialist, Dr Richard Stanhope.
Dr Charmian Quigley, of drug giant Eli Lilly, manufacturers of growth hormone (GH), says that short children are 'juvenilised, teased and bullied'. She goes further, citing a large Swedish study of adults which looked at suicide rates in relation to height: A reduction in height by 5cm led to an increase of suicide of 9%.
Evidence like this convinced the Food and Drug Administration in the US to act.
It recently licensed the use of recombinant GH (a newer safer form) for so called 'small normals' - children who are not GH deficient, and who are healthy but simply shorter than normal.
"Shortness only became a disease when a treatment became available," says Dr Linda Voss, of the Peninsula Medical School who co-ordinated the Wessex Growth Study.
Normal but 'concentrated' as Sarah Teather calls it, is, it seems, no longer normal.
Who decides what is normal? Usually doctors with charts - but they constantly change their minds about what constitutes normal.
Take blood pressure and blood cholesterol levels, both markers of heart health.
Blood pressure naturally rises with age. It used to be thought so normal that older people with very high blood pressures weren't even treated.
But today any reading consistently above 140/90 in a person of any age is treated aggressively because its now known that this will dramatically reduce the risk of stroke and heart attack.
A total blood cholesterol level of six used to be deemed normal.
Now, no more than 5.2 is the target figure.
To reach this would mean medicating three quarters of all Britons over 65 with cholesterol lowering drugs, making not taking medicines abnormal.
Such extensive medicalisation troubles many - but doctors claim that the impact on cardiovascular disease would be so great as to be worth it.
An even more dramatic shift came with BMI, or body mass index, which relates weight to height and is used to gauge weight.
The top end of "normal" BMI used to be 28 but suddenly it was changed to 25 because the Americans reluctantly agreed to fall in line with the rest of the world.
"Literally overnight 30 million people became overweight," says Barbara Moore, of Shape Up America.
So normal one day and in need of treatment the next? Yes.
But when you question how reliable BMI is as an indicator of normality, you are suddenly on boggy ground.
"It's hopelessly crude on an individual basis," says Dr Philip James, of the International Obesity Task Force.
Muscly fit men, such as rugby players and athletes - even George Clooney, that superb specimen of manhood - are deemed obese if one uses BMI to assess them.
And as big becomes, well, more normal, we are no longer able to view weight objectively because our comparator is those around us.
We have an even bigger problem when it comes to our children.
As dietician Paul Sacher says: "When parents say that their children are overweight, you can be certain that they are actually obese."
If the problems with defining normality with weight, height and heart health have suddenly become apparent, think how difficult things become when trying to assess what someone is feeling inside their head to diagnose depression.
We generally judge such things in others by noting changes in behaviour, but think how difficult this is for doctors who may be meeting a patient for the first time.
The use of ratings scales may help, but there is another difficulty with mental health.
Writer Andrew Solomon interviewed hundreds of people for his book 'The Noonday Demon: an atlas of depression.
As he puts it: "People have their own normality, and what seems to one person to be an acceptable normality would seem to another person to be intolerable.
"Some people are completely undone by what seems to be mild depression, others integrate what seems like severe depression into their lives."
Defining normal, creates abnormal. Deviating from the usual creates the unusual. And I have found in this series, normal is anything but.
Am I Normal? is on Tuesdays on Radio 4 at 2100BST beginning on 22 August 2006.
You can also listen online for seven days after each broadcast at Radio 4's Listen again page.