Once we had to put up with the bodies we were born with, but rapid advances in medicine are making it possible to make more and more changes to our bodies. People with money to burn can have bigger breasts and smaller noses. About half of the human body (by weight) can now be replaced. This is only the beginning.
The answer may be that the womb is a sterile environment, whereas the world outside it certainly isn't. An open wound can let all sorts of pathogens get into the body. It seems that around the time we are born, the healing process is permanently accelerated, so that wounds close as soon as possible to prevent infection. It is this accelerated healing that causes scarring. Work on finding ways of slowing it down again is well advanced - in a few years time a series of injections could prevent disfiguring scars forming after injury or surgery.
People whose lives depend on an organ transplant are likely to be more worried about whether a donor can be found in time than about whether the operation will leave scars. There is a global shortage of organs for transplantation. And for those people who do have transplants, the biggest problem is preventing their bodies rejecting the transplant. All cells have surface proteins embedded in their outer membrane, which differ both between and within species. If cells with foreign surface proteins are introduced into the body, they will be attacked and destroyed by the immune system.
Organs from transgenic animals are likely to be widely used in the near future and could save many lives. There are problems, of course. Firstly, the organs are essentially pig organs, even though they contain a few human genes, and pigs don't live as long as humans. How long will their organs survive in human bodies? Secondly, pigs are not going to be much use to people who need new ears, noses or fingers. What would be ideal, for both people and pigs, would be the ability to take a few cells from the person who needs a transplant and use them to grow whatever body part is required. There would no risk of rejection if cloned organs were used, because the cloned organs would have exactly the same set of cell surface proteins. Transplant patient would no longer have to take immuno-suppressant drugs for the rest of their lives, drugs which make them vulnerable to infection.
The fundamental problem with this idea is that although every cell contains all the genes needed to make a complete human being, cells become specialised. In other words, if you stick skin cells into a Petri dish, they'll grow into more skin cells (if they grow at all), not into another human being. This is because as cells differentiate, certain genes get turned on and off. A skin cell expresses only those genes needed to be a skin cell, rather than the genes for being a muscle cell or for growing into a kidney.
Theoretically, if you knew which genes to turn on and off, you could make a skin cell grow into whatever you wanted. The only problem is that humans have got about a hundred thousand different genes and at the moment we haven't got a clue what most of them do. The Human Genome Project is changing this rapidly - in ten years time we should have a pretty comprehensive picture of what genes exist and what they do.
Better still would be learning how to get the human body to regenerate itself. Many animals, like newts and lizards, are capable of regenerating lost bodyparts. Perhaps one day we will learn how to stimulate human cells to regenerate, enabling us to regrow fingers and toes and arms and things. (No doubt this would be much appreciated by the Bobbits of the world.) Maybe even vital organs like the heart could be regenerated, if people were kept on life supports systems until the new organs were capable of taking over.
So in the future people could be fully restored to health after suffering diseases and injuries which now leave people disabled for the rest of their lives. Plastic surgeons would no longer be limited to stretching skin to try and hide the wrinkles - they could replace old skin with new. Amputees might be able to regrow lost limbs after a few months or years. Replacing or repairing parts of the body might become nearly as routine as changing car tires or redecorating a house.
This would only involve tidying up our DNA and swopping genes between people. But things aren't likely to stop there. Entirely novel genes could be designed, which would give our bodies extra capabilities. For example, our livers could be given genes that would enable them to synthesize nutrients and vitamins which we can only obtain from our diets at present, like vitamin C. People who need expensive drugs could be given the genes needed for their bodies to manufacture these drugs. And this is only the tip of the iceberg.
But it is not just about vanity. People might want change their bodies so they can do things better. For example, athletes might reshape their muscles and bones to squeeze out that extra little bit of performance. Pianists could have their fingers extended.
I haven't yet mentioned the most dramatic consequence of such advances in medicine. That is the subject of FutureLife.
BodyNotes
90% of our DNA is junk
And not all of this junk DNA behaves itself. Some bits jump around from one place to another, which can be nasty if they land in the middle of an important gene and bugger it up.
Amputees might be able to regrow lost limbs
Such an advance can't come soon enough. There are thought to be over 100 million landmines around the world, left over from various conflicts. Most of these mines are designed to disable rather than kill people, because injured personnel require more care than dead ones. Seventy people are maimed or killed by left-over mines every single day. Oxfam and many other organisations are campaigning to have these cruel weapons banned.
xfam Home page
Athletes might reshape muscle and bone
Would this be allowed? Well, it might be virtually impossible to detect.
But if one athlete beats another just because he happened to inherit a more suitable body for sprinting, for example, then it could be regarded as unfair not to allow the loser to make changes which would let him to compete on an equal basis.
Could prevent disfiguring scars forming
The implications may go well beyond the cosmetic. For example, every time an athlete injures a muscle, scar tissue is formed, so the muscle will never be the same again. And it is now known that nerves in the central nervous system (brain and spinal cord) can't repair themselves because tiny scars are formed after injury, which prevent the nerves cells reforming connections. This is why spinal injuries may leave people paralysed for the rest of their lives.
However it is not yet clear whether this kind of internal scarring could be prevented in the same way as external scarring.
Differentiate
Become specialised. That is, some cells become muscle cells, other will become nerve cells, etc.
Cloned
To clone something means to grow an identical copy. So when you grow plants from cuttings, you are growing clones of the original plant.
Expressed
A gene is "expressed" when it is used to make the protein for which it codes.
Human Genome Project
The aim of the Human Genome Project is to construct a complete map of the human genetic blueprint. In the short term this will enable people (and foetuses) with genetic predispositions to certain diseases to be identified. In the longer term it should lead to better drugs with less side effects, new cures and gene therapy for inherited diseases.
The patenting of human genes is provoking a lot of controversy. If patenting is not allowed, progress will be far slower, as companies will not be prepared to invest in research. But if it is allowed, once a particular gene is patented by one company, no other companies will be prepared to develop any therapies based on that gene. The rush to patent genes is also discouraging the free exchange of information between scientists.
Pathogens
Disease causing organisms, mainly viruses and bacteria.
Secret location
No, I can't tell you where it is. But I can tell you that it is being kept secret because of fears that animal rights activists will attempt to "liberate" these animals. I wouldn't want to be a transgenic pig myself, but surely killing pigs to save human lives is better than killing pigs because you're fond of bacon.
Theoretically
Experiments have already been done on frogs. If you take the nucleus (the part of the cell that contains the genes/DNA) from a tadpole and inject it into an egg whose original nucleus has been destroyed, then the egg will (usually) grow into a frog. This works because the egg contains proteins that switch genes on and off, effectively "resetting" the genetic programme.
However if you use a nucleus from an adult frog, the egg develops into a tadpole but not into an adult frog - because more genes have been turned on or off in the adult frog and the egg cell lacks the specific proteins to reverse these changes.
So by injecting the appropriate proteins into a cell, it should be possible to make it grow into whatever we choose.
Tidying up our DNA and swopping genes between people
This is what sex and evolution is all about. We'd simply be speeding up the process.
Turned on and off
At any one time, only a few of the genes possessed by a cell are actually being used (to make proteins). When cells differentiate they have to stop making some kinds of proteins and start synthesizing others, so some genes must activated or turned on, and others must be turned off. For example, cells that are destined to become muscle cells have to start making all the proteins from which muscles are constructed.