The Secret Life of Twins
BBC1, Wednesday 30 September 2009/Thursday 1 October 2009
Presented by Chris van Tulleken and Xand van Tulleken
Have you ever wondered what it must be like to look at oneself in the flesh rather than in the mirror? I have, and I have gone on to wonder also what it must be like to grow up with an identical sibling and the psychological benefits and disadvantages of this relationship. This two-part programme I hoped would look at both the physiological and psychological impact of having and being an identical twin. The first part re worked the nature versus nurture debate looking at how our characters and bodies are formed; 'are we born or formed?' The second part looked at how lifestyles can affect our genes.
When you consider that only 4,000 UK couples a year (1/2 per cent in world population terms) have identical twins, the value of the information these twins hold for scientists is like 'gold dust', especially if the twins have been separated at birth. So, inevitably, some of the examples the programme used which mirrored the examples that scientists were using in studies around the world were worrying especially if the participants had been separated at birth.
The first programme showed us twin 'gatherings' at St Thomas' Hospital in London and in Twinsburg, Ohio. The main pair of twins throughout the two programmes consisted of two male doctors, and you saw them participating or rather 'competing' in different tests that researchers provided at St Thomas'. The tests were trying to establish if it was just the genes (which are shared 100 per cent by identical twins,) that govern the way we think, behave and what choices we make. Other twins in Australia were shown helping Australian scientists to understand the genetic component of mental illness and this interestingly led to the researcher propagating the theory that low self-esteem was estimated as 50 per cent genetic and 50 per cent environmental.
The most interesting and touching twins were two little Chinese girls separated at birth and not acknowledged to be identical twins by the Chinese Authorities. However the adopting couples - one Norwegian and one American - realised they were identical, had DNA testing done and kept in touch with each other. The programme showed the reunion of these twins at six years old and - with the encouragement of both sets of parents - they instantly began relating to each other, showing how their genetic code overcame the fact that they spoke different languages and came from different adoptive cultures. The worrying part of this film watched by vigilant researchers and viewers was the parting of these two children showing obvious distress. It led one to ponder on many issues of both the powerlessness and powerfulness of the environment; the concern caused by inter-cultural adoption and the possible long-term psychological issues for these children.
Two other sets of twins also threw up different and interesting nurture issues. Two men, one who lived the 'good' healthy life in New Zealand exercising and controlling alcohol and food intake, and the other, his brother who lived unhealthily in the UK, both developed a serious heart condition about the same time. The other couple of female twins were separated until they were in their mid-forties and were brought up with completely different faiths - one Jewish and one Catholic - which seemed to be irrelevant as compared with the genetic issues.
In the second programme they concentrated on the issues of life styles affecting genetic make-up. These included a valuable study done on the genetic basis for leukaemia with two small girls and how potentially the evolution of the disease could happen in the uterus. Ageing and sexual preferences of different twins was also analysed, which led to the link between nature and nurture - epigenetics - and this showed how possibly genes could be switched off and on with the potential for chemically modifying genes in the future. Epigenetics is at the cutting edge of medicine with many hopes attached to this regarding controlling diseases.
This programme tried to show that in studying identical twins we could learn about what we are like, who we are and what makes the difference between us all. There was a lot that was fascinating to watch, a lot that reinforced how important genes are, and a lot to think about how genes maybe be manipulated in the future for the benefit of us all. However, it was hardly the 'secret life of twins' and I was left with many questions about some of the psychological issues that the programme didn't answer and the effect of making the programme on some of the participants.