Guys with classically masculine facial features, such as square jawlines and pronounced cheekbones, may produce sperm of a lower quality than men who don’t share the same features, a new study finds. 
 
 The findings rely on an oft-studied phenomenon in the animal kingdom known as the phenotype-linked fertility hypothesis. It states the greater presence of male sexual ornaments signals a stronger vitality for reproduction. These ornaments are typically anatomical in nature, such as the set of feathers on one species of bird or the song of another. 
 
 But in humans the hypothesis hasn’t gotten much attention. So researchers recruited a group of 62 college students, from both Colombia and Spain, to rate the physical attractiveness of select pictures of men who had donated their sperm earlier in the experiment. Researchers censored all but the subjects’ faces, including hairstyle, to minimize external influences. 
 
 ketrin1407, CC BY 2.0 
 
 They compared levels of attractiveness, masculinity, and sperm health to determine which features, if any, correlated with one another. The results were decidedly lukewarm. While they did find a significant negative relationship between masculine features and sperm motility, the significance vanished when the team controled for outright unhealthy sperm. It was the outliers, in other words, that were doing the heavy lifting. 
 
 So, the hypothesis didn’t seem to ring as true as they might have expected. But they did find a relationship between how males perceived males versus how females perceived males. The subjects most likely to rate the faces as attractive were other men, and particularly among the Spanish students. 
 
 “This suggests that male facial cues may provide culture- and sex-independent information about male fertility,” they wrote. However, it also indicates humans may be poor judges of attractiveness when it comes to people who are culturally near to them. And males, on average, are worse judges than females. 
 
 What does the study say about the phenotype-linked fertility hypothesis as it relates to humans? Unfortunately, not much. A large camp of evolutionary biology likes to believe the animalistic traits we possessed as ancient hominids have changed to accommodate modern-day mating rituals. All women want tall, protective men in good social standing, they are apt to say. Beneath our material, hi-tech infatuations are primal desires that prove even if we’re a population of smart animals, we’re still animals. 
 
 Science is increasingly finding these theories don’t hold much water. Tall men, with their far-reaching gaze, may have the advantage over short men when it comes to scanning the plains for enemies, or dinner, but if a woman’s goal is to keep a tidy house and send her kids to college, short men — the biological underdogs — tend to prevail. 
 
 Prior research has upheld the link between elevated testosterone levels and poor sperm. In their study, masculine men were thought to have low sperm counts in part because they don’t need as much, being the sexual dynamos they are. However, since the researchers were also measuring attractiveness, it’s worth mentioning the attractive men (who weren’t necessarily masculine) had better sperm. Chalk this one up to round jaws and low cheekbones. 
 
 Source: Soler C, Kekäläinen J, Núñez M, et al. Male facial attractiveness and masculinity may provide sex- and culture-independent cues to semen quality. Journal of Evolutionary Biology. 2014. ||||| Sure, he looks good. But how about his sperm? 
 
 That might not be such a ridiculous-sounding question, now that a new study has identified a link between men's facial attractiveness and the quality of their semen--with handsome, masculine-looking guys having slightly lower-quality semen than other men. 
 
 "To [the] best of our knowledge, this is the first demonstration of the phenomenon," study co-author Dr. Jukka Kekalainen, adjunct lecturer in the Centre for Evolutionary Biology at the University of Australia in Crawley, told The Huffington Post in an email. 
 
 The researchers have no ready explanation for their finding, although previous research has shown that high testosterone levels can harm sperm production, the New York Daily News reported. And the finding seems to be at odds with the so-called phenotype-linked fertility hypothesis, which holds that females prefer handsome males because their offspring may enjoy hereditary benefits, such as better health and higher intelligence. 
 
 For the new study, which was published in the September 2014 issue of the Journal of Evolutionary Biology, a team of researchers from Spain, Australia, and Colombia performed semen analyses on 50 Caucasian students recruited from the University of Valencia. Next, photos of the men's faces were shown to heterosexual men and women in their twenties, including Caucasians and blacks. 
 
 The women evaluators were asked to rate the men as if they were looking for a long-term mate. The men evaluators were asked to rate the men as they thought women would rate them. 
 
 The researchers also performed an "anthropometric analysis" of the facial characteristics of all 50 men, measuring the size of their eyes, the width of their cheekbones and nostrils, and other markers that previous research identified as masculine features. And finally the researchers compared the men's facial features with the motility (movement), morphology (structure), and concentration of the men's sperm cells. 
 
 In addition to looking for the link between masculine-looking faces and sperm quality, the researchers wanted to know if men's sperm quality was related to their handsomeness. 
 
 "And we found that in fact it is," Kekalainen said in the email. 
 
 But does that mean women eager to find a mate capable of fathering children should be wary of handsome men? Maybe not--at least not until more research corroborates the finding. As Kekalainen said in the email, "we would need more studies to demonstrate the causation and mechanism behind this finding...before giving any mating tips to the females." ||||| The Royal Society A pair of faces from the Face Research Laboratory study to evaluate women's preferences. The image on the left has more masculine features like thicker eyebrows and a wider jaw. 
 
 (See Correction & Amplification below .) 
 
 Sometime within the past year, nearly 4,800 women participated in an experiment at Faceresearch.org, the online psychology laboratory of the Face Research Laboratory at the University of Aberdeen in Scotland. They were young women, mostly in their early- to mid-twenties, and all identified their ethnicity as white. Later, researchers at the lab would confirm from IP address data that the participants came from 30 countries including Argentina, Sweden, Russia, Australia and the United States. The women's country of origin was an important part of the experiment. 
 
 After registering on the site, the women clicked through to a listing of psychology experiments, including "face preferences" and "attractiveness at different ages." Upon making their selection, they received instructions, in English or in translation, telling them they would be presented with pairs of men's faces. For each set they would need to select the face they considered more attractive and indicate how much they preferred it to the other one. 
 
 Take the Test Click here to participate in Faceresearch.org's experiment, "Facial Attractiveness." Note: Users must first register with the site. 
 
 The faces, it turned out, looked eerily alike and yet subtly different, like identical twins. They were created by software that masculinizes or feminizes a person's features in a few keystrokes. Only by examining the faces closely could one discern that the man on the left, say, had slightly rounder eyes and a narrower jaw than the one on the right. Some of the faces had slightly thinner lips than their doppelgängers, or wider-set eyes, or thicker archless brows. It took most women fewer than 10 minutes to click through the 20 pairs of male faces and select which ones they found hunkiest. 
 
 After crunching the data—including the women's facial preferences, their country of origin and that country's national health index—the Face Lab researchers proved something remarkable. They could predict how masculine a woman likes her men based on her nation's World Health Organization statistics for mortality rates, life expectancy and the impact of communicable disease. In countries where poor health is particularly a threat to survival, women leaned toward "manlier" men. That is, they preferred their males to have shorter, broader faces and stronger eyebrows, cheekbones and jaw lines. The researchers went on to publish the study in this month's issue of the scientific journal Proceedings of the Royal Society: Biological Sciences. 
 
 The New York Times; Getty Images (5) Click to enlarge image. 
 
 To a person unfamiliar with the field of evolutionary psychology, this may sound a little far-fetched. How is it even possible to link a woman's masculinity preferences to the health of her nation? The answer begins with the theory of sexual selection. It goes that women are the choosier sex because they take on most of the risk and burden of reproduction and child rearing. While a man can sleep around with 100 women in a year's time and have 100 kids, a woman who sleeps with 100 men in a year will only have one baby (barring multiples). She has more at stake in each pregnancy. Therefore, it is in her best interest to at least choose a high-quality mate. And one of the hallmarks of a quality male is good health. 
 
 But what does health have to do with masculinity? The link is testosterone, the hormone behind manly muscles, strong jaws, prominent eyebrow ridges, facial hair and deep voices. Testosterone is immunosuppressive. This means a man must be healthy and in good condition to withstand its effects on his development. Testosterone is also linked to other traits related to strength: fitness, fertility and dominance. From an evolutionary perspective, masculinity is basically man's way of advertising good genes, dominance and likelihood to father healthier kids. When disease is a real threat, as it had been—and arguably still is—heritable health is invaluable. 
 
 In the Company of Men Heracles and Hemingway: A brief look at notions of manliness throughout history Heracles Getty Images The son of Zeus (also called Hercules) symbolized strength and masculinity in Greek mythology. He had numerous affairs with women and fathered many children. Alexander the Great Getty Images He may have been a military genius, but scholars have also remarked on his feminine appearance. He was always depicted as clean shaven in images—Greek rulers were previously shown with beards—and Plutarch wrote about his "melting blue eyes." Louis XIV Getty Images The Sun King helped bring fanciful costumes and wigs into fashion for men in 17th-century France. Wigs started out more natural-looking, but quickly grew much taller and fuller. Ernest Hemingway Getty Images He is often described as macho in personality as well as prose, thanks in part to his spare writing style and love of big-game hunting and bullfighting. Norman Mailer Getty Images Machismo is a common theme in Norman Mailer's books. In an interview he once said, "There are pleasures in being macho, but there are great anxieties." James Dean Getty Images The actor became an icon for brooding masculinity in 1950s films like "Rebel Without a Cause." Clint Eastwood Getty Images His stoic, tough-guy roles have even inspired academic essays about images of masculinity in his films. 
 
 Masculinity, however, can come at a high price. Women often think of high-testosterone types as uncooperative, unsympathetic, philandering, aggressive and disinterested in parenting. In fact, there is evidence that they really do have more relationship problems than other men. In a small study led by psychologist James Roney at the University of California, Santa Barbara, 29 women were asked to look at photos of men and rate their masculinity and fondness for infants. (The men had already been tested for child-friendliness and testosterone levels.) The men who were rated as the most masculine generally had higher testosterone levels; the women also were generally accurate in assessing child-friendliness. 
 
 In another study of 2,100 Air Force veterans, men with testosterone levels one standard deviation above the mean were 43% more likely to get divorced than men with normal levels, 31% more likely to leave home because of marital problems, 38% more likely to cheat on their wives, and 13% more likely to admit that they hit or hurled things at them. 
 
 In this light, manifest masculinity doesn't sound like such a good deal. At least not in a significant relationship. A woman might be attracted subconsciously to a high-testosterone man because he'll give her kids an edge health-wise. But if health comes at the expense of fidelity and good parenting, how much does masculinity really matter? 
 
 The apparent answer is not so much—if you're a woman living in a country with a decent health-care system and few harmful pathogens. While a masculine father's "good genes" may confer health advantages to children, so do good medical attention and a clean environment. In the Face Lab study, women with the weakest masculinity preferences tended to live in some of the healthiest countries: Sweden, Finland, Denmark and Austria. Other countries in the study with low masculinity preferences are Romania, Greece and New Zealand. Women with the weakest masculinity preferences of all lived in Belgium, a country considered to have one of the best publicly funded health-care systems in Europe (alongside Denmark and the Netherlands in the health-care index). 
 
 Meanwhile, women with the strongest masculinity preferences tended to hail from the countries with higher disease and mortality rates and some of the poorest scores on the health-care index: Mexico, Brazil, Bulgaria and Argentina. (The researcher included only white subjects to control the experiment, and Asian and African nations were not included in the study.) 
 
 And where does the U.S. stand in the masculinity ranking? The answer is fifth out of the 30 countries in the study, one of the highest. This is, after all, the home of James Dean and Clint Eastwood. And where does America stand in the health index ranking? Twentieth of 30 countries, one of the least healthy. 
 
 This is not to say that cultural factors other than health care don't play a role in women's mate preferences. The Face Lab researchers acknowledge that there are variables they did not take into consideration. For instance, women's equality and control of resources would likely influence preference for masculinity. The same goes for violent crime. In cultures where physical strength and dominance are a primary means of security and social mobility, a masculine mate seems like a valuable asset. Yet, generally speaking, the researchers found that a nation's health index explained more of the variation in women's masculinity preferences than did many culture-specific female norms identified in previous studies. 
 
 The big question that comes of the study is this: Is it possible that modern medicine—and by extension modern life—inadvertently devalues masculinity? Possibly. Is the Marlboro Man, that smoking-hot icon of American manhood, under threat of being extinguished? Given American women's apparently strong masculinity preferences, the answer is no. We are not ready to get rid of our macho men. (Then again, we also have yet to improve our health index ratings.) Yet there are some smoke signals that suggest change is just over the horizon. 
 
 As the social environment shifts, so may women's mate preferences. While Stone Age forces once wired women to associate strong cues of masculinity with their children's chance of survival, times are changing. The promise of improved health care in America could be one example of a shift. 
 
 Another is women's financial freedom. In 1970, women represented only 43.3% of women of the labor force, compared to 55.8% today. Moreover, the recession in America has been a tremendous blow to men in traditionally masculine jobs such as construction and manufacturing; 82% of job losses affect men. Right now in the U.S. many families find themselves economically dependent on one working parent: Mom. Over 70% of mothers have jobs outside the home. No longer as reliant on men's genes or jobs to ensure the health and wealth of their children, women may come to value other qualities in a mate. It may become evolutionarily adaptive to prefer men who are cooperative, communicative, caring and better parents over traditional "manly men." 
 
 Then again, women have always asked, why must we choose either/or in a mate, and not all-in-one? In a study of 107 American married couples, evolutionary psychologists David Buss and Todd Shackelford found that beautiful women (as determined by averaged ratings of eight teams of male and female interviewers) want it all in a partner: masculine, physically fit, loving, educated, desirous of home and children, a few years older than themselves and with a high income potential. 
 
 While exceptionally attractive (or wealthy) women may indeed capture this ideal male, most are forced by circumstance to settle for the best combination of traits. Some husband-seekers trade off masculinity for companionship and good parenting. Others forfeit compassion in exchange for wealth. ("I want a man who's kind and understanding," Zsa Zsa Gabor once griped. "Is that too much to ask of a millionaire?") To secretly have it all, some women adopt a "dual mating" strategy—marrying a solid, faithful guy and enjoying trysts with hunks. As a result, up to 10% of babies born in some populations have fathers who are presumed to be their biological dads but aren't. 
 
 Will any of this change as American women become increasingly secure economically, socially and medically? A study led by psychologist Fhionna Moore at the University of St. Andrews finds that as women's level of "resource control" increases—that is, they become more financially independent—their preference for good-looking men increases. So will it be considered progress if women start pursuing "metrosexuals"—impeccable guys who exfoliate, order salads for dinner and carry man purses? This remains an open question, and it's fun to speculate. Perhaps the vision of artist Corita Kent will come to pass: "Women's liberation is the liberation of the feminine in the man and the masculine in the woman." 
 
 —Jena Pincott is the author of "Do Gentlemen Really Prefer Blondes?" 
 
 Correction & Amplification 
 
 Studies related to women's perceptions of masculinity and preference for attractive males were led by researchers at the University of California, Santa Barbara and the University of St. Andrews, respectively. A previous version of this article incorrectly referred to those institutions as the University of Santa Barbara and the University of Andrews.
– Macho guys may attract more women, but the quality of their sperm might not be of he-man standards, a new study suggests. Oddly, the sperm of good-looking guys—but not necessarily macho ones with square jaws and distinct cheekbones—is just fine, reports Medical Daily. The link was found when researchers analyzed the semen of 62 Caucasian men, then compared its motility and structure to facial measurements of masculine traits and ratings of their attractiveness, the Huffington Post explains. Scientists theorize that the macho man trades virility for a gravely voice and ripped arms, and high testosterone hinders sperm production. Meanwhile, the study casts doubt on the belief the "phenotype-linked fertility hypothesis" (read: fancy feathers and pretty songs attract more ladies) applies to humans. A study that claimed short guys are preferred by women over tall ones, long believed to have the evolutionary upper hand, has also poked holes in that theory. But don't revamp your mating habits just yet, girls—researchers say their findings need further study. (Short guys are also less likely to divorce you.)