By James Melik Business reporter, BBC World ServicePeople can use relationships at work to kick-start their career, but relationships can also turn out to be repressive and hinder careers from flourishing.Research shows that a large proportion of workers have had amorous relations with colleagues, but what if they are rivals or the boss is involved?There is always the danger of exploitation, according to Peter Handel at Carnegie Training. He says the real problem is when one person has power over another.Mr Handel trains personnel departments in 75 countries on how to deal with such a sensitive and difficult subject."There are two real issues," he says. "How can one be sure that the relationship is consensual, without any subtle or direct coercion, and is there a conflict of interest."Company policiesDifferent companies have different rules about their staff entering into liaisons with co-workers.Some companies impose a complete ban, an approach that Mr Handel believes is counter-productive.He agrees, however, that relationships can cause problems that interfere with the smooth running of an organisation."If a co-worker is sleeping with the boss, how do you know if that person is not getting better pay rises and better assignments?"Many companies will move one of the participants elsewhere, but that can create further problems of a different kind."If you move a junior partner, it may not be very fair, but if you move a senior partner, you may lose a good leader," he says.Besides, moving their staff elsewhere may not be an option for smaller companies.And simply getting rid of them is not easy either.There are legal aspects to consider when redeploying or sacking staff, especially in the United States."If you fire someone, you are open to accusations of sexual harassment," Mr Handel says.Many law firms specialise in such cases, so he warns employers: "Don't do anything you don't want on the front of the Daily News the next day."Aphrodisiac of powerThe conventional wisdom is that relationships with colleagues are to be deplored - and if it is with the boss, then you should run a mile or get the lawyers in.Research compiled by Andrew Kakabadse, professor of international management development at Cranfield University in England, shows that 60% of all workers have had a powerful intimate relationship with a co-worker.Describing what he means by intimate, he says it is more than a friendship and "one step before something becoming physical"."A large number of relationships change into a sexual relationship," he says, "regardless of the person's religion or country of origin."He realises that it might be hard to believe that six out of 10 colleagues are involved in an intimate relationship, and that the reaction of the other four out of 10 is: "I don't believe you."He says people start to believe the figures when they ask themselves: "Why is the boss making these decisions about these guys?""In the workplace, you usually find women having affairs with more senior men," says Rod Liddle of the Spectator magazine."Men go for youth and beauty. Women are attracted by the aphrodisiac of power, the earning ability and someone able to look after the children," he says.There are many factual and fictional examples of the abuse of power - from the casting couches of Hollywood to favouritism because of pillow talk."We cannot police such activities," says Mr Liddle.Unwilling complianceThe National Organisation for Women in the US reports that between 50% and 75% of employed women have experienced some form of sexual harassment at work.The line between flirtation and harassment is very fine, however.According to the American Management Association, half of romances at work lead to a lasting relationship or marriage.In some cultures, the workplace is the most natural place for people to meet their future partners."In Kenya, many ministers have at least two wives," says columnist Wycliffe Muga, "and many of the younger ones are women the men have met at work."But more recently, in a subtle cultural shift, many Kenyan men are now finding their first wife at work.In 2006 the Kenyan government brought in the Sexual Offences Act, which, among other things, aimed to eradicate sexual harassment in the workplace.This has actually made things more difficult for women workers."It is harder for women to find jobs, because companies are afraid that every jilted woman would bring claims of sexual harassment," says Mr Muga.Source: BBC