Dublin, IRELAND -

"For men, there is a moment in life, usually in your late 30s or 40s, when you speak one day and, to your great surprise, hear your father talking." -- John Masterson, Doctor of Psychology

Up our way, if a person has a particular trait it will invariably be put down to genetic predisposition.

Be it a penchant for violent behaviour, a fondness for the opposite sex, a tendency to mistake the property of others for ones own or a talent for the accordion, it will be explained by, "He/she didn't lick it off the ground."

There is an ongoing debate over the relative power of nature and nurture. Is the key in our genes or in our family, friends and experiences?

Research has tipped the scales overwhelmingly in favour of nature. But new findings are shedding light on how heredity and environment interact. In many areas of investigation the jury is still out. For instance, the portion of a population's IQ variability attributable to the effects of genes has been studied for more than a century, yet it remains controversial. In other words, nobody has proved that intelligence is not inherited.

Dr. Masterson is a devout believer in the nature theory. He claims that we have little or no control over many of the ways we behave, " ... it is programmed from the moment you are conceived; the combined contributions of your two parents make up you and there is nothing you can do about it."

In 1979 Jim Lewis, a steelworker, and a clerical worker, Jim Spring, met. They were identical twins who had been separated five weeks after birth -- thirty-nine years earlier -- and raised by families eighty miles apart in Ohio. The correlation between their traits and characteristics was striking. Both spoke with the same inflections. Both hated baseball, married women named Linda, di vorced them and married women named Betty. Both vacationed on the same half-mile of beach in Florida.

Seven thousand sets of twins were studied at Minnesota Centre Twin and Adoption Centre. Study of twins found that attributes and behaviour owe at least as much to heredity as to environment. Things such as extroversion, traditionalism, leadership, career-choice, religious conviction and vulnerability to stress are inherited.

One study concludes that happiness is 80% heritable. It has been found that while pessimism and optimism are genetic only optimism is affected by environment. (I was once told that you should always borrow money from a pessimist ... he doesn't expect it back.)

For somebody used to nine-inch cavity blocks and bus-engines the following is somewhat mind-boggling: The human body has 100 trillion cells, each equipped with a complete set of DNA, distributed among 23 pairs of chromosomes. If set out in a continuous strand the DNA from a single cell would be 6 ft. long. And each cell's DNA is made up of some 3 billion nucleic components. (Amazing what you hear in the canteen in between discussions about the waitresses' anatomy and the controversy over the abolition of Rule 42).

Molecular biologists worldwide are burning midnight oil trying to find the one-in-three-billion bit that may explain a particular behaviour. According to Dean Hamer, Chief of Gene structure and Regulation at the National Cancer Institute in Bethesda, [Maryland, USA] " ... we think that there may be ten genes altogether that influence anxiety. But there may be a hundred or a thousand." George Howe Colt describes it in Life:

" People with just a few of those anxiety genes might feel nervous when they have to give a speech. Those with a few more might cringe when the phone rings. And those with a full compliment might be so timed they rarely leave the home."

Some social commentators argue that linking genes and violence is blaming the victims and shifts the focus away from the real culprits -- poverty, racism and unemployment. Yet brain research shows that violent males tend to have low levels of the chemical serotonin; levels associated with depression, aggression and impulsivity, all traits with high heritability. (There seems to be a great shortage of serotonin among soccer supporters.)

Bethesda Psychiatrist Stanley Greenspan says,

"When a trait appears to be influenced by genes, people assume it's not changeable, but we can change the way genes express themselves. We can change behaviour."

Psychologist Thomas Bouchard, Director of the Minnesota Twin study, believes,"a lot of books say you can do anything you want, but we have real doubts about that. It's not that you can't but we suspect it's been done at a cost."

So, whatever idiosyncrasies of mine ?you have observed through my monthly ramblings try and remember that " I didn't lick them off the ground."