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Prince Harry approves of this important research.

When it comes to a man’s hotness quotient, there are the usual shallow suspects. But let’s just blame evolution for a woman’s fondness for broad shoulders and a v-shaped torso.

Now, a new study published in the journal Evolutionary Psychology finds that women like their men to have a little blush to their faces. Who knew? But that could explain why so many women find Prince Harry and Bill Clinton so darn yummy; their rosy faces may actually discount the fact that one is, well, a prince and the other, a former U.S. president. Or maybe not. 

In any case, red really does rule, eliciting a range of emotions and behaviors in humans and other species, according to newly published research in the journal Evolutionary Psychology.

Among some male birds, fish and primates, the color red acts as a kind of beacon, broadcasting social dominance, testosterone levels and influencing mate selection. Humans actually show physical avoidance reactions (they move their bodies away) from red-covered IQ test booklets rather than green or grey ones. We even perform worse on cognitive tests after exposure to red when compared to other colors. But it can help us hook up. Women who wear red are more attractive to men. And men who wear red get a second look from more women. Red even influences athletics. If you want to be on a winning sports team, wear a red jersey.

The mystery, it seems, was whether women found that facial redness actually makes a man seem more attractive or dominant.

In the (small) study, 45 Caucasian women were shown photos of 21 Caucasian men, all with neutral expressions. The women could then manipulate the complexions of the men, adding red or yellow tones, to make them appear as aggressive, dominant or attractive as possible. Dominance, aggression and attractiveness were not defined for the trial participants.

What the women did was increase redness, while holding lightness and yellowness constant, when asked to make the men look dominant. They added even more red when asked to make the men look aggressive.

But when it came to attractiveness, think a little pink. It’s a rosy glow that women deemed smokin’ hot.

Researchers speculate that slight degree of ruddiness, which doesn’t make a man look too aggressive or too dominant, may be viewed as a sign of good health and fitness, a turn-on in any species.  

But getting too red in the face is just one big sexual buzzkill.

The researchers found the uber-red of aggressiveness puts a big damper on a man’s perceived attractiveness. In other words, the benefit of being with a man who is healthy and dominant outweighs the potential risks of being with a man who is perceived as too aggressive.

In other words, guys, a little rosy can go a long way.

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The other day, a few media outlets in the New York region covered the story of a woman who can’t seem to stop having orgasms, which would seem joke-ready but can actually be a nightmare.

While the New Jersey woman’s condition has not been formally diagnosed, it appears she has persistent genital arousal disorder (PGAD), something we explored years ago. 

The syndrome usually manifests as a constant blood engorgement of the female genitals, mainly the clitoris. This creates a sensation of needing “relief.” Cue the jokes. But imagine constantly sensing the need for orgasm at work, on the bus, while visiting with friends, and then finding no relief, or only very temporary relief, if you masturbate. Genitals can become highly sensitive, and sore. Sufferers describe feelings of isolation and mental anguish.

Unfortunately, nobody is quite sure what causes it or how to treat it, but, according to Jim Pfaus, a researcher at Montreal’s Concordia University who studies the neuroscience of sexual response, and who is currently engaged in studying persistent genital arousal, there are enough clues to develop a working theory.

“The root cause,” he explained, “may be an irritation of the clitoral sensory nerves.” The brain interprets this sensation and sets off a cascade of events.

A brain region called the pro-optic area responds to dopamine signaling by sending out instructions for the body to prepare for sex, as if a woman has been engaged in foreplay when, in fact, she’s not remotely in a sexual context. Blood flows to the genitals. “So we think that this blood flow is in a state of hyperarousal in women with PGAD,” Pfaus said. “They get engorgement quickly, reach orgasm quickly when they try to relieve themselves. It shares features with premature ejaculation and priapism” in men.

That’s consistent with observations others have made. For example, Barry Komisaruk at Rutgers University found that of a group of 18 women with PGAD, 12 had cysts on nerves in the sacral region of their spines. The cysts may be stimulating clitoral nerves.

A variety of drug therapies (there’s even one report of a physical therapy involving manipulation of muscles in the region) have shown to help. SSRIs, commonly used for depression, seem to provide some relief. But Pfaus believes the drug varenicline (Chantix, commonly used for smoking cessation) is most promising. It works by interrupting the signaling that leads to dopamine release. Blood stops flowing.

While the therapy has worked in scores of women, Pfaus said, the drug isn’t perfect. “Unfortunately it comes back when they go off it.” 

Brian Alexander (www.BrianRAlexander.com) is co-author, with Larry Young PhD., of "The Chemistry Between Us: Love, Sex and the Science of Attraction," (www.TheChemistryBetweenUs.com) to be published Sept. 13.

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In the classic movie White Christmas, Bing Crosby jokingly tells Rosemary Clooney that by eating the right sandwich before bed, he can make sure he dreams about redheads, or blondes. If only we could all influence the content of our dreams so easily.

Well, a dream researcher in Hong Kong named Calvin Kai-Ching Yu, of Shue Yan University, says we can, at least a little.

For a study released last week in the journal Dreaming, he sampled 670 people, mostly university students, two-thirds of whom were females. He had them complete surveys about the intensities of their dreams, how often their dreams contained specific themes (such as flying, being chased, suffocation, and so on), and personality traits. They also indicated how often they slept on their sides, face up (supine), or face down (prone) on a five point scale from “never” to “almost every time.”

When he analyzed the numbers, he found that the prone sleepers, as a group, were much more likely to score highly on what he calls the Dream Motif Scale (DMS), regardless of their personality type. Motifs like “persecution,” “erotomania,” and “sex” appeared significantly more frequently.

He concluded that “this study provides the evidence that dream experiences, and in particular dream content, can be influenced by body posture during sleep.”

In other words, sleeping face down is more likely to give you intense dreams featuring several common themes. Among the persecution motifs, for example, people reported “being tied up,” “being locked up,” and “unable to move.”

But why would position so influence the content of our dreams? Kai-Ching Yu believes that the prone position provides more intense physical stimulus, making it tougher to breathe, for example, and making our bodies feel more constricted.

“The unconscious brains of the dreamers try to make sense, and even make use of, the external stimuli,” he told NBCNews.com.

It’s something like the dreams we have – common across cultures – when we have to urinate. We’re sleeping, but the pressure begins influencing our dream content so we start dreaming about bathrooms, or having to go. Also, when we’re face down, our genitals are receiving more stimulus from the bed and sheets, he speculates, so our brains incorporate that into sex-related dreaming.

He may be right, but there are reasons to be skeptical. First, a common problem in dream research is that people often don’t accurately recall their dreams even when they’ve just awakened. Also, while many people may think they know what position they sleep in, they’re often wrong. The dream scales Kai-Ching Yu used in his study were invented by him and, he said, they have not been validated by other researchers, though he has used them in many studies and gotten consistent results.

But the biggest reason for skepticism is that other scientists argue we’re cut off from the external world when we’re asleep. We’re in a completely internal realm – at the mercy of what sleep researchers from Harvard have called “a virtual reality system” without meaningful responses to the outside world, like the touch of sheets or the pressure of our bodies laying face down.

He doesn’t completely disagree, but said “I believe that the brain during sleep is not at all totally detached from the external world, and somatosensory stimuli, including those stemming from the environment, are probably incorporated into dream content more often than people observe or are aware of.” This is especially true, he thinks, at the unconscious level. That’s where our brains try to make sense, even if distorted, of what the body’s feeling.

Brian Alexander (www.BrianRAlexander.com) is co-author, with Larry Young PhD., of "The Chemistry Between Us: Love, Sex and the Science of Attraction," (www.TheChemistryBetweenUs.com) to be published Sept. 13.

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By Jeanna Bryner
LiveScience

Women may not need a guy, a vibrator, or any other direct sexual stimulation to have an orgasm, finds a new study on exercise-induced orgasms and sexual pleasure.

The findings add qualitative and quantitative data to a field that has been largely unstudied, according to researcher Debby Herbenick, co-director of the Center for Sexual Health Promotion at Indiana University. For instance, Alfred Kinsey and his colleagues first reported the phenomenon in 1953, saying that about 5 percent of women they had interviewed mentioned orgasm linked to physical exercise. However, they couldn't know the actual prevalence because most of these women volunteered the information without being directly asked.

Since then, reports of so-called "coregasms," named because of their seeming link to exercises for core abdominal muscles, have circulated in the media for years, according to the researchers.

"Despite attention in the popular media, little is known scientifically about exercise-induced orgasms," the researchers write in a special issue of the journal Sexual and Relationship Therapy released in print this month. [5 Myths About Women's Bodies] 

Herbenick and her colleagues used online surveys to gather their data, which included answers from 124 women who had experienced exercise-induced orgasms and 246 women who reported exercise-induced sexual pleasure. Most of the women, ages 18 to 63 and an average age of 30, were in a relationship or married and 69 percent said they were heterosexual.

The researchers found that about 40 percent of both groups of women had experienced exercise-induced pleasure or orgasm on more than 11 occasions in their lives. Most of the women in the "orgasm" group said they felt some level of embarrassment when exercising in public places.

The "orgasm" group mostly said during the experiences they weren't having a sexual fantasy or thinking about someone they were attracted to.

Of the women who had orgasms during exercise, about 45 percent said their first experience was linked to abdominal exercises; 19 percent linked to biking/spinning; 9.3 percent linked to climbing poles or ropes; 7 percent reported a connection with weight lifting; 7 percent running;  the rest of the first-time experiences included various exercises, such as yoga, swimming, elliptical machines, aerobics and others. Exercise-induced sexual pleasure was linked with more types of exercises than the orgasm phenomenon.

Answers to open-ended questions in the survey revealed some interesting details, the researchers found. For instance, the abdominal exercises tied to orgasms seemed to be particularly associated with the exercise in which a person supports their weight on their forearms on a so-called captain's chair with padded arm rests and then lifts their knees toward their chest.

The open-ended questions also revealed the orgasms tended to occur after multiple sets of crunches or some other abdominal exercise rather than after just a couple repetitions; they also seemed to happen after the woman had really exerted herself.

"Many of these women talked about it happening even as children," Herbenick said during a telephone interview, adding that some indicated an experience at age 7 or 8.

"We had at least one woman in the study who was a virgin, and she really loved that she could have these experiences at the gym," Herbenick said. [10 Surprising Sex Statistics]

The researchers aren't sure why certain exercises lead to orgasm or sexual pleasure, though Herbenick hopes to tease out the trigger in ongoing research.

"It may be that exercise, which is already known to have significant benefits to health and well-being, has the potential to enhance women's sexual lives as well," Herbenick said, adding that it isn't clear whether these exercises could actually enhance women's sexual experiences.

The research has various implications regarding women's sexuality. For one, orgasm and sexual desire have topped women's list of sex concerns, with around one out of four women not reaching orgasm during sex. The researchers suggest "it may be that physical exercise has been overlooked in clinical approaches to women's orgasm."

Second, scientists have long debated the evolutionary context of the female orgasm and its link to sexuality and reproduction. However, if many women are experiencing orgasm during exercises not related to sex, then exercise-induced orgasm may reveal what orgasm does and does not have to do with sex or reproduction, the researchers note. [G-Spot: Science Can't Find It]

In addition, exercise-induced orgasms may be one way for scientists, and women themselves, to learn about the process of orgasm. "It may be one way for women to learn more about how their bodies work in that regard," Herbenick said.

As for how other scientists may react to the finding: "I think from having talked with colleagues, while some people have heard of these [exercise-induced orgasms], many of our colleagues haven't either," Herbenick told LiveScience. "So I think that's going to be interesting," seeing the reaction. She added that some might question, "'Is this a tooth fairy type of thing or does it really happen?' I have no doubt that it happens."

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By Wynne Parry
LiveScience 

A low-pitched voice in a man is associated with a litany of masculine traits: dominance, strength, greater physical size, more attractiveness to women, and so on. But new research strikes one trait off that list: virility.

An Australian study looked at male voice pitch, women's perceptions of it, and semen quality. Their first finding was no surprise: Women like deep voices and consider them masculine.

But contrary to expectations, they also found that these men aren't better off in the semen department. In fact, by one measure of sperm quality — sperm concentration in ejaculate — men with the attractive voices appeared to have a disadvantage.

This is a surprise because females, both humans and of other species, are believed to glean information about male virility through secondary sexual traits, such as facial hair and muscle mass in humans and other traits in other animals, such as colorful plumage in birds.

In the case of voice pitch, the researchers from the University of Western Australia suggest there may be a trade-off at work. In other words, traits associated with dominance and attractiveness, such as physical strength or a deep voice, may come at the cost of reduced sperm quality, they write in a study published Dec. 22 in the journal PLoS ONE.

For instance, higher testosterone levels are associated with a deeper voice, more masculine features, more dominant behavior and success in obtaining sexual partners. Although testosterone plays an important role in the formation of sperm, however, high levels of it can actually impair sperm production, they write.

To conduct the research, the team recruited 54 men to provide voice recordings and semen samples. Their recordings were analyzed by software and ranked by 30 female volunteers on attractiveness or masculinity.  

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• 5 Myths About the Male Body
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By Stephanie Pappas
LiveScience

A 54-year-old woman showed up in the emergency room at Georgetown University Hospital with her husband, unable to remember the past 24 hours. Her newer memories were hazy, too. One thing she did recall: Her amnesia had started right after having sex with her husband just an hour before.

While sex can be forgettable or mind-blowing, for some people, it can quite literally be both at the same time. The woman, whose case was reported in the September issue of The Journal of Emergency Medicine, was experiencing transient global amnesia, a rare condition in which memory suddenly, temporarily, disappears.

People with transient global amnesia suffer no side effects, and the memory problems usually reverse themselves in the span of a few hours. It's a rare condition, affecting only about 3 to 5 people per 100,000 each year. But what makes transient global amnesia so eerie is that researchers aren't sure what causes it, or why patients remain otherwise chatty and alert while missing large chunks of their memories. [Inside the Brain: A Journey Through Time]

"We don't know very much about the cause," said Sebastian Ameriso, a neurologist at the Institute for Neurological Research in Buenos Aires, who was not involved in the 54-year-old woman's case. "It causes a lot of alarm, but this is not a stroke or an event that causes damage to the brain. It's almost always very benign."

Mind-erasing activities
Sex can trigger transient global amnesia, as can other physically strenuous activities. People in their 50s and 60s are the most likely to experience an episode, but strangely, most people with transient global amnesia have it only once. In most cases, the amnesia is anterograde, meaning people have trouble forming new memories. Sometimes, people also experience transient retrograde amnesia, forgetting some portion of their previous memories. In the case of the 54-year-old woman at the Washington, D.C., hospital, the last day was a fog, and she had been forgetful and confused since having sex.

As with most patients, the woman's brain scans using magnetic resonance imaging (MRI) and computed tomography (CT) showed nothing unusual and no damage to the brain. By the time she left the emergency room, her symptoms were almost gone.

The closest thing to an explanation researchers have for this sex-triggered amnesia is that the problem may not begin in the brain, but in the neck. In a January 2010 study published in the journal Stroke, Ameriso and his colleagues conducted sonograms of the necks of 142 patients who'd experienced transient global amnesia within the last week. They found that 80 percent of the patients had what is called insufficiency of the valves in the jugular vein.

This vein, which runs down the side of the neck, carries spent blood from the brain back to the heart. Valves in the veins prevent blood from flowing backward toward the head, but if the valves don't close sufficiently, blood could seep back upward.

Memory mysteries
The best guess for what might be happening is that patients unwittingly trigger the transient global amnesia by raising the pressure inside their abdomens. This is called the "Valsalva maneuver," familiar as the "bearing down" people might do when lifting weights, defecating or even having sex. The increased pressure increases the resistance to blood flowing down the jugular veins, and insufficient valves may allow deoxygenated blood to push back up the neck. Oxygen-poor blood then "piles up" in the veins draining the brain, especially in central brain regions that are key to memory formation. The result could  be transient amnesia.

What this explanation doesn't cover is why most people with transient global amnesia experience it only once, Ameriso told Livescience.

"This doesn't explain why this would happen only once while we do this Valsalva maneuver many times during the day," he said.

Whatever the cause, transient global amnesia can be upsetting. In one case reported in 1964, a man lost his memory the moment he orgasmed, causing him to exclaim, "Where am I? What's happened?" [10 Surprising Sex Statistics]

People with transient global amnesia usually rush to the hospital in great distress, Ameriso said — which is not a bad thing, given that sudden memory loss can also herald a stroke or other serious neurological problems.

For doctors and patients alike the most important thing is a quick diagnosis, Ameriso said. Otherwise, patients can languish in the hospital for days, waiting anxiously for test results.

"It's important to be able to diagnose this very quickly, looking for the insufficiency in the veins," Ameriso said. "If you can confirm that this is the case, you can save a lot of money."

You can follow LiveScience senior writer Stephanie Pappas on Twitter @sipappas. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and onFacebook.

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