BBC said:Our level of happiness throughout life is strongly influenced by the genes with which we were born, say experts.
An Edinburgh University study of identical and non-identical twins suggests genes may control half the personality traits keeping us happy.
The other half is linked to lifestyle, career and relationships.
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BBC News : Genes 'play key happiness role'
Remains to find which genes control happiness levels. DNA tests will be able to tell us our propensity to be happy in the future.
This is just one of thousands of things DNA tests will help us know from our early childhood, in order to lead a better life. Knowing that we have a poor physical endurance, that we are intolerant to some products (e.g. lactose), or particularily sensitive to some products or environment are all ways of knowing what to do or not to do to be happier. So "happy genes" may also involve not having many medical conditions that put strains to our daily life. People who are rarely ill, have no allergies, and feel energetic most of the time have more chances of leading a contended life than those who don't have the same luck.
But could a too high level of "natural happiness" lead to easy satisfaction, and therefore to a reluctance to effort, hard work and self-improvement ? Aren't the most successful people in life those that are contantly dissatisfied, now matter how well they perform ?
Other studies reveal that happiness is also related to sex (not a big discovery). Well, actually, men with lower testosterone levels feel more easily depressed says a study by the University of Western Australia. As testosterone levels decrease with age, men are more likely to be depressed as they grow old, and not just because of old age itself.
Testosterone acts as a stimulant, a bit like coffee, but with powerful psychological effects too. It is what motivates men to seek power, control, knowledge, money, fame or any other attribute likely to heighten their status and increase their chance of finding sexual partners. Without testosterone, motivation for countless activities drops, which leads to depression. This is partly why pre-menopaused women are more prone to depression than men of their age.
In East Asian cultures, the male Yang represents activity and vigour, while the female Yin is associated with apathy and depression. This may be a bit extreme and caricatural, but it shows that ancient people already observed this fundamental role of male and female hormones on mood.