If you are a woman and think you are good-looking, chances are you are more prone to cheat on your partner.

At least that is what a recent study by social psychologist Norman Li found.

According to the study, done together with another researcher at the University of Texas in Austin, Texas, women with higher levels of oestradiol - a key sex hormone -were rated as more attractive by themselves and were more willing to cheat in a relationship, but not more likely to have a one-night stand.

Dr Li, 42, who teaches at the Singapore Management University (SMU), is a specialist in mating, possibly the only one of his kind in Singapore.

His research involves exploring the science of attraction, love and lust in people.

The research headings outlined in his curriculum vitae read like titles of chick lit with catchy phrases such as All For Love? and The Booty Call.

He has even appeared in television programmes such as The Sex Files, which was produced by the Discovery Channel in Canada, and The Science of Seduction, produced by the BBC.

But the American-born lecturer did not get into this line of research for being a Don Juan in his younger days, although he did admit to having his first crush in preschool at age three. Or that is what his mother, a computer systems analyst, told him, since he cannot remember it. His father is a history professor.

He also denied using any seduction tactics when courting his 22-year-old wife, Ruth, who was his student at the University of Texas.

Li had started off as an economics graduate who began his career as a foreign currency options trader, working in the busy exchanges of Chicago and Philadelphia.

He said: "I was just interested in making money at that time. I wanted to find the easiest and fastest way of earning money."

The work was financially rewarding but it was far from easy. Work started as early as 5.30am and he would be on his feet the entire day. He often skipped meals and got little sleep. The environment at his workplace was "brutal", with people constantly shouting at one another.

He quit after a year and decided to pursue a PhD in finance. But that turned out to be too boring and theoretical for his liking and he left after a year of studies.

He then joined an investment consultancy firm which managed pension funds and attended night classes at the same time to "satisfy my intellectual curiosity".

On a whim, he chose to attend a psychology class. From the first lesson, he knew he had found his calling.

"As soon as I took it (the course), I loved it. I've always liked to study how people think, behave and feel. But I didn't realise there was a course of study for that," he said.

He took up more psychology classes as his interest grew. For one of his classes, he designed a project on mate preferences. He found that given a "tight budget" on qualities that they want in a partner, men tend to prioritise looks while women choose social status.

The project proved to be the turning point in his career. His professor was so impressed that he suggested that Li take up postgraduate studies in psychology.

Much to his parents' chagrin, he left his financial career a few months later, at age 30, and spent the next two years taking up more ad hoc psychology classes and helping various professors with their research at Northwestern University in Chicago.

His parents eventually accepted his decision to start a new career from scratch.

He later enrolled in the Arizona State University's social psychology postgraduate programme and got his doctorate five years later.

Said Li: "It has always intrigued me what makes someone attractive to certain people. And now I have the opportunity to study this."

He decided to marry his financial knowledge with psychology and came up with the theory that people constantly but subconsciously make cost-benefit analysis while forming relationships.

He applied his knowledge in economics to the study of how people choose their partners. He found that men see attractiveness in women as a necessity instead of a luxury because subconsciously, they associate beauty with fertility and the ability to bear children.

On the other hand, women regard social status in men as a necessity in their partner because subconsciously, they want someone who can support the children and family.

When asked if this theory is the reason he is married to a beautiful young woman, Li answered: "Yes, she is a beautiful woman. But we also have a lot in common. Both of us value family above all else."

His wife Ruth had put her undergraduate studies on hold to accompany him to Singapore when he got his job at SMU last year. The couple have a three-month-old son, Jasper.

Being a love expert had not spared him from relationship troubles of his own.

He was previously married to a postgraduate course mate, but the marriage did not work out and they separated four years later.

"I may be an expert at initial attraction but I have yet to study relationship maintenance," he joked.

Last week, he started on a new project which will study attitudes towards mating and marriage in Singapore and the United States.

So why are many Singaporeans not getting married and procreating, we asked.

Said Li: "One possibility is that people are caught up with work. Things are expensive here and it is hard for people to feel established and ready to start a family."

For those who have yet to get hitched, he has some tips which could prove very useful.

For one thing, do not expect to find a potential wife or husband at pubs or clubs.

"It's like going to Takashimaya and expecting to purchase something cheap. Chances are you won't find it," he said.

Instead, he suggested that the men take up cooking classes where they can meet women. The women can take up a sport, such as tennis or golf, as they are more likely to meet men in these places.

Men do not necessarily need to be rich but they should find something they are good at, which they will be respected and admired for.

"When you are a big fish, women will like you," he said.

Women, unfortunately, have it tougher as looks play a major role in initial attraction. But with grooming, their chances can be improved.

But here's a consolation. Men also want women who are kind and caring.

After all, it is the pretty ones who are more likely to cheat in a relationship. But this is not deterministic, he stressed.

He said: "It's just one factor among many other factors. There are many other things that influence whether someone is going to be faithful, such as values, religion and opportunities."