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Cityfile has partnered with Dr. Helen Fisher to bring you the latest insight into love and romantic attraction. A renowned biological anthropologist, Dr. Fisher has conducted extensive research in the fields of human sexuality, love and marriage. She serves as Chief Scientific Advisor for the internet dating site Chemistry.com.

Question: What leads people to cheat? Can cheating be okay? And can a serial cheater ever change?

Answer: There are lots of reasons people cheat...

Some people want to get caught, so they can patch up a marriage; other people do it get out of a marriage. Some seek attention. Some want to feel more attractive. Some just want more sex. Others crave drama or danger. A few are looking for revenge. Many more want to prove that they're still young.

But it's worth noting that cheating is universal. I've looked at adultery in 42 societies and found it in every one. So I suspect there are some biological underpinnings to cheating. A million years ago a wedded man who had an affair was more likely to have extra children, and an adulterous woman received extra food and protection for the children she already had. If these kids lived, they probably passed along this appetite for adultery to the next generation. But I don't think men are, on average, more adulterous than women. If they were, who are all these men sleeping with?

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As for the last part of that question, yes, people can and do change. But it often takes a shock of some sort. Some people quit drinking and taking drugs. Some have a spiritual experience or narrowly escape death. Some get caught and realize the importance of their marriage. Some people just fall in love with someone so deeply that cheating no longer holds a thrill. But typically something needs to change before this happens. But it's worth noting that research suggests that some people are biologically more prone to adultery than others. There's a specific gene involved in this; it's been called the "monogamy gene." This isn't to say that biology is destiny. Some people just have a bigger battle with Mother Nature.

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