The latest scientific research into "desirable" and "essential" traits men and women look for in a companion has again reaffirmed a common gender stereotype: men want beautiful, slender women, and women prefer rich and financially stable men.

Researchers from Chapman University in California conducted a study of more than 28,000 heterosexual participants aged 18 to 75 and asked what they look for when searching for a mate.

They found that the gender of participants was by far the strongest predictor of what people wanted in a long-term partner, and those with more "desirable" traits have a stronger bargaining hand and can be more selective when wading through the dating pool.

"We looked at the extent to which attractiveness and resources are 'desirable' versus 'essential' to men and women when they are looking for a long-term partner," said David Frederick, assistant professor of psychology at Chapman University and a co-author on the study, reported EurekAlert. "We've known for a long time that men care more about attractiveness in a long term partner, and women care more about resources."

For example, men were more likely to prefer a "slender" partner than women, with 80 percent of men saying this was an important factor compared to only 58 percent of women who said "slender" was an important quality. Men were also more likely than women to say it was "desirable/essential" that their partner was good looking, 92 percent to 84 percent.

Women, on the other hand, preferred a partner with a steady income, with 97 percent saying this was a desirable trait, while only 74 percent of men said the same. A higher percentage of women also said they want a mate who makes as much money as them and has a successful career.

Both men and women who were happy with their own personal appearance did not necessarily desire a partner who is physically attractive to them, but they did have stronger preferences for a partner who was good looking and slender.

The study also found that the older participants got, the less they cared about physical attractiveness, wealth or a successful career.

The study, titled, "Mating markets and bargaining hands: Mate preferences for attractiveness and resources in two national U.S. studies," is scheduled to be published in the January issue of the journal Personality and Individual Differences.