Reproduction is a less costly activity for men than it is for women. After all, guys can do their part in a matter of minutes, and they don’t have to carry babies around for nine months afterward or breastfeed. This isn’t going to change either, unless scientists eventually turn the plot of Arnold Schwarzenegger’s worst movie ever into reality.

Men’s lower cost of reproduction, in turn, gives them more reproductive potential. We need look no further than the Guinness World Records for most prolific mother and father ever for evidence of this: Russian peasant Feodor Vassilyev reportedly gave birth to just 69 children in her lifetime, compared to the 888 fathered by Moroccan Emperor Moulay Ismael.

Is it really possible to father 888 children, you ask? According to modern scientists, the answer is yes—and all you need is a harem of 65-110 women. Well, that, and a really high sex drive and some Gatorade.

Due to these differences in reproductive costs and potential, evolutionary psychologists have long claimed that the sexes have evolved different mating preferences. These preferences are thought do be adaptive, enhancing the odds of reproductive success. Specifically, when looking for a long-term mate, they argue that women tend to look for men who can provide, whereas men tend to look for women who are healthy and fertile.

In other words, women give more consideration to men’s resources, while men pay more attention to women’s physical appearance.

So just how big is the divide between what men and women desire? According to a new set of studies published in the journal Personality and Individual Differences, gender is actually the single biggest predictor of what we’re looking for in a long-term partner. At the same time, however, there are also some striking similarities in terms of what men and women want.

In this paper, researchers considered data from two of the largest national U.S. studies on mating preferences ever conducted. Altogether, more than 28,000 heterosexual adults participated and provided demographic information (including age, income, education and how confident they felt in their own physical appearance), as well as information on how important certain traits are in a potential romantic partner.

Consistent with evolutionary theorizing, men (92 percent) were more likely than women (84 percent) to say it was desirable or essential for their partners to be generally good-looking. Men thought it was more important for their partners to have slender bodies, too (80 percent of men vs. 58 percent of women).

In contrast, women (97 percent) were more likely than men (74 percent) to say it was important for partners to have a steady income. Likewise, compared to men, women felt it was more important for their partners to make a lot of money, to make at least as much or more money than them and to have a successful career.

The fact that these findings emerged did not surprise the researchers (just as I’m sure it doesn’t surprise many of you); however, the size of the gender differences was unexpected.

As described in an email to me by one of the study’s authors, Dr. David Frederick, an assistant professor of health psychology at Chapman University: “What surprised us was just how much gender mattered much more than anything else we measured – more than age, education, income or confidence in appearance.”

Why is this gender difference important?

“Understanding these preferences helps us understand many of men’s and women’s behaviors,” says Frederick. “It helps us understand the greater widespread dissatisfaction with weight among women, part of which is driven by pressure to attract a partner. It can help us understand part of men’s striving for higher income and assertively negotiating for raises, because income affects not only their ability to pay for dates but also their likelihood of attracting a partner.”

Frederick cautions us to be mindful of the fact that within a given gender group not everyone has the same desires. As he and his co-authors argue in their paper, what men and women see as desirable and essential in a potential partner depends, to some degree, on what they themselves bring to the table.

Many of the studies’ findings support a “mating market” perspective, meaning that those who possess the traits most desired by the opposite sex have a stronger “bargaining hand,” thereby allowing them to be more selective when looking for a mate.

For instance, according to Frederick, “Men who felt more confident in their appearance or who had higher incomes had stronger preferences for a slender partner.” In other words, guys who possess more of the traits that women want have a competitive advantage over other men and, therefore, don’t feel as much need to compromise when it comes to their own preferences.

Although the results of this research reveal that men and women differ in the overall importance they place on looks and money, there are some important similarities worth noting between the sexes.

For example, when asked how important it was to have a partner who was physically attractive in their own eyes, men and women did not differ. Likewise, an overwhelming majority of men and women expressed a desire for a conventionally good-looking partner with a steady income.

Put another way, both men and women prefer sexy partners who have money. It’s just that, as a group, men give somewhat more emphasis to the former and women to the latter.

It’s also worth pointing out that the size of these gender differences in mating preferences is not static—it can vary across contexts, including culture and age. As some evidence of this, the value people placed on appearances and bank accounts was lesser among older men and women in this set of studies.

According to Frederick, “One interpretation of this finding is that as people get older, they start placing less importance on looks and money and relatively more importance on having a wonderful companion they can count on through thick and thin.”

In other words, as the biological imperative to reproduce winds down, so does the gender divide, with men and women ultimately coming to desire the same thing.

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Justin Lehmiller, PhD is a sex educator and researcher at Ball State University and author of the blog Sex and Psychology. Follow him on Twitter @JustinLehmiller.