The old adage that women can’t ‘have it all’ may have more than an element of truth in it, according to scientists.A new survey has revealed that high powered career women who have stressful jobs may struggle to find love.In addition to long hours, which can make finding time for romance hard, the stress of a busy job causes an increase in the level of the hormone cortisol, which research suggests makes women less good-looking to men.Men were asked to rate the attractiveness of women’s faces and those who had high levels of the stress hormone were rated lower.The researchers also found that the women deemed to be more attractive carried an ‘ideal’ amount of fat – neither too much nor too little.The research, conducted by the University of Turku, in Finland and published in the Royal Society journal Biology Letters, suggest that this effect might be because those who have high stress levels tend to be less healthy overall, and our faces reflect both how healthy someone is as well as their fertility.Men are biologically more likely to be attracted to women who are both healthy and fertile, and thus can bare them children, even if this reasoning behind attractive is subconscious.Cortisol helps reduce the immune system and increase metabolism under stressful conditions – meant to help the ‘flight or fight response’ but over production can have a negative effect on health and has been linked to heart disease.Similarly, while some fat is essential to health and fertility in a woman, too much has a negative effect on both.While women in high powered jobs can aim to keep their body fat at a healthy level, they may be less able to control their bodies response to the strain of their jobs.Dr Markus Rantala who led the study, said: ‘Perhaps, then, low levels of cortisol signal health in female faces.‘This would be consistent with many studies in humans that have found that stress has strong negative effect on health, including immune function, heart disease and susceptibility to cancer‘An alternative explanation is that facial attractiveness signals reproductive potential, which is mediated partly by stress hormones.’However, the good news for ladies looking for love is that men are in much the same boat; their level of cortisol has been found to rise if they are around a beautiful women, making them less attractive to us!