We’ve heard (and written) plenty on the struggle of women to reach equal footing with men in the sciences. Now, two of the more prominent women in American science are talking up the issue before they accept their Nobel Prizes next week.
Elizabeth Blackburn and Carol Greider, along with a third American, Jack W. Szostak, won this year’s award in medicine for showing how chromosomes protect themselves as cells divide. Speaking in Sweden in advance of the award ceremony, Blackburn said the setup of scientific careers prevents more women from reaching the upper echelon. “The career structure is very much a career structure that has worked for men. But many women, at the stage when they have done their training really want to think about family . . . and they just are very daunted by the career structure. Not by the science, in which they are doing really well” [AP].
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Researchers have long sought an answer to burning question of why women live longer on average then men (you know, other than the fact that, as Harry Belafonte puts it, “man smart, woman smarter“). Now a new study in Human Reproduction by Japanese researchers reinforces the argument that the fault lies in men’s genes, a conclusion they reached by taking males completely out of the picture.
They studied mice created with genetic material from two mothers, but no father. This was achieved by manipulating DNA in mouse eggs so the genes behaved like those in sperm [BBC News]. The scientists then implanted those sperm-behaving eggs into female mice, creating 13 “bimaternal” mice. On average, these fatherless mice lived a third longer than those conceived in the usual manner, according to study leader Tomohiro Kono.
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It’s been a bad month for chemicals and masculinity. Last week 80beats covered the discomforting link found between the chemical bisphenol A (BPA), which is found in any number of consumer products, and erectile dysfunction. Now the villains are phthalates, chemicals used to make plastics softer and more flexible. A new study in the International Journal of Andrology has raised a storm of concern that prenatal exposure to these chemicals could make boys less masculine in their play preferences.
Phthalates, which block the activity of male hormones such as androgens, could be altering masculine brain development, according to Shanna H. Swan, a professor of obstetrics and gynecology at the University of Rochester Medical Center and lead author of the new report [Los Angeles Times]. To test whether that link extended into behavior, Swan’s team tested women for phthalate levels midway through their pregnancy and then checked back in on the children four to seven years later.
The researchers asked parents to report their children’s patterns of play, but they knew they also had to separate any potential phthalate effect from the “nuture ” side of question. To determine how parental views might sway behavior, parents completed a survey that included questions such as, “What would you do if you had a boy who preferred toys that girls usually play with?” They were asked to respond with whether they would support or discourage such behavior, and how strongly [TIME].
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By altering a female fruit fly’s pheromones, researchers have created an insect with so much sex appeal that it even attracts males of other species. But in a surprising twist, they didn’t boost the levels of some courtship chemical–instead they created flies that lacked all pheromones, which were then besieged suitors. The discovery suggests pheromones can be back-off rather than come-hither signals. The finding could lead to a better understanding of the chemical signals that help flies and other animals interpret the world, including how to select a mate and how to distinguish other species [Science News].
The study, published in Nature, also found that males who lacked all pheromones attracted unwelcome attention from other males, who attempted to copulate with their heads. Says lead researcher Joel Levine: “It’s amazing what you see…. There are some pretty crude movies” [Nature News].
To conduct their experiments, the researchers identified the cells on the inside of the fly’s exoskeleton (pictured in glowing green) that produce the pheromones, and inserted a gene into the fly genome to kill all these cells. The manipulated flies provided a sort of blank canvas to allow the scientists to test the role played by each chemical – and how the chemical signals interacted. “We found that one compound – one that males transfer on to females when they copulate – kept other males away,” said Dr Levine. “It’s the male’s way of sort of protecting his investment” [BBC News].
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Image: Jean-Christophe Billeter
Trouble is mounting for the South African athlete who was suspected of having an unfair advantage in women’s track events because of male characteristics. After 18-year-old Caster Semenya thumped the competition at an 800-meter race in Berlin, sports officials announced that Semenya would be subjected to a battery of tests to determine her gender. Now, unconfirmed sources have reported that the tests showed Semenya has both female and male reproductive organs, and her future in women’s sports is in doubt.
Newspapers in Australia reported that while Semenya’s external genitalia is female, she doesn’t have ovaries and instead has internal testes that produce the hormone testosterone. If the reports are accurate, Semenya probably benefited from that hormone boost by gaining muscle mass. But it now seems clear that there is no disciplinary action to be taken, because even if Semenya has high male hormone levels, it is not because of medical cheating. But that leaves a moral and ethical quandary and a medical issue which anyone else in the same position would be able to work out in private – for Semenya, it is all public [ABC Sport].
Experts says that based on the information reported, Semenya may have a condition called androgen insensitivity syndrome, in which the fetus develops functional testes, but then stops developing male characteristics. As a result, the baby develops down the “default” female route. The testes are there but usually do not descend and remain hidden in the body and the condition does not become apparent until adolescence when the girl does not start her period [BBC News]. Medical experts also note that internal testes can grow malignant tumors, and say that some doctors advise removing them as a precautionary measure.
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A petition that seeks a posthumous apology from the British government for its treatment of Alan Turing, a key WWII codebreaker and a father of computer science, has garnished more than 5,500 signatures. Among the signatories are the evolutionary biologist Richard Dawkins and the novelist Ian McEwan.
In 1952, Turing was found guilty of gross indecency after admitting to a sexual relationship with a man (homosexuality was illegal at the time). His sentence? Estrogen injections in an experimental chemical castration treatment, along with the removal of his security clearance, thereby costing him his job for the U.K. Government. Two years later, he ended his life with a poison-laced apple–but not before he had made significant contributions to the world of computer science. In 1936 he established the conceptual and philosophical basis for the rise of computers in a seminal paper called On Computable Numbers, while in 1950 he devised a test to measure the intelligence of a machine. Today it is known as the Turing Test [BBC].
Many say that had Turing’s life not ended prematurely, he could have advanced the worlds of computer science and codebreaking even further. “There is no doubt in my mind that if Turing had lived past age 41 his international impact would have been great and that he likely would have received a knighthood while alive” [CNN], wrote computer scientist John Graham-Cumming, who initiated the petition.
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Image: flickr / Wikimedia Commons. A statue of Turing at the University of Manchester.
When 18-year-old Caster Semenya blew past the competition in the women’s 800-meter race at the World Athletics Championships in Berlin this week, she got more than a gold medal. The South African athlete ran straight into a controversy about both the nature of gender and hers in particular. Some other runners contend that Semenya, with her stereotypically masculine build, is really a man, while the more temperate governing body, the International Association of Athletic Federations, says it needs to determine if she has male characteristics that give her an unfair advantage. To settle the question, the IAAF has ordered tests by a gynecologist, an endocrinologist, a gender expert, and a psychologist.
Gender expert Richard Auchus says assigning sex was hardly as easy as sizing someone up visually…. “For 99 percent of the population it’s easy to determine…. But one percent of the population have conditions that make it not so straightforward” [The New York Times]. In the 1960s, athletic federations began testing athletes by scraping cells from their mouths and testing them for a pair of X chromosomes, which typically establishes a person’s sex as female (as opposed to the XY chromosomes typically carried by males). But the tests were halted in the 1990s as critics pointed out that there are medical conditions that lead individuals with two X chromosomes to develop masculine characteristics, and others that mean individuals with one X and one Y chromosome never develop masculine characteristics. Some other individuals also exist outside the usual sexes of XX females and XY males; these may include males who are XXY, further confusing the tests [Nature News].
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In some lizard species, it’s not just genetics that determines whether males or females will clamber out of hatching eggs. Some species are also governed by nest temperature, like the the three-lined skink lizard: Seven years ago, Australian biologist Rick Shine showed that low nest temperatures could overrule genetics, and cause embryos to develop into males. Now, Shine and his colleagues have taken their skink research a step farther, showing that the size of an egg’s yolk also plays a mysterious role in the ultimate sex of the offspring.
Physiologist Rachel Bowden, who was not involved in this research, says the study “muddies the water” for everything researchers thought they knew about sex determination in lizards…. “It’s clear that they have sex chromosomes. But it’s also clear that those sex chromosomes can readily be overridden by some other factors. So, the process that leads to sex determination might be fairly plastic” [The Scientist].
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When a heterosexual Humboldt penguin couple rejected their unhatched egg this spring, zookeepers at Germany’s Bremerhaven Zoo found a happy home for the abandoned egg in the nest of gay penguin pair, Z and Vielpunkt. “Another couple threw the egg out of their batch,” the zoo’s vet said in a statement. “We picked it up and put it in the nest of the gay penguins” [The Advocate]. The couple then incubated the egg for more than a month before hatching a healthy chick that is now about four weeks old.
Z and Vielpunkt have been caring for the chick just as a heterosexual penguin couple would, say animal experts. They’ve been taking care of their chick around the clock; it’s still too young to feed itself, so the dads feed him fish mash [Los Angeles Times]. But the pair is not the first same-sex penguin couple to raise a child: a pair at Central Park Zoo in New York also hatched an egg, but only after they tried to incubate a rock until they were given an abandoned egg. Another male penguin couple were removed from their colony in a Chinese zoo last year when they repeatedly tried to steal eggs from male-and-female pairs. (In a rather ingenious move, they actually replaced the eggs they were stealing with rocks.) [Los Angeles Times]
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Researchers have more evidence that takes aim at the old stereotype that boys are better at math than girls. Psychologist Janet Hyde had previously studied scores on standardized math tests in the United States, and found no difference in performance between girls and boys. Her new study expands the scope of the work by analyzing international data. She and her colleague analyzed studies from around the world on math performance along with gender inequality as measured by the World Economic Forum’s Gender Gap Index. This index measures the gap between men and women in economic opportunity, educational attainment and other socioeconomic factors [LiveScience].
They found that countries with poor gender equality, like India, had a larger gender gap in math, while in countries with excellent gender equality, like the Netherlands, girls performed as well as boys. If males really did have an innate advantage in math, the researchers note, that advantage should be obvious throughout all these cultures. Instead, the study suggests that cultural issues are the basis of the math gender gap.
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The preference for sons in traditional Chinese families has led to a vast gender disparity in China: A study has found that there are currently 32 million more boys than girls under the age of 20. While Chinese officials have acknowledged that the country’s “one-child” policy has led to a gender imbalance, the new study offers the first hard data on the extent of the disparity. The study included nearly five million people under the age of 20 and covered every county in China. It found that overall ratios of boys were high everywhere, but were most striking among the younger age group of 1-4 years, and in rural areas, where it peaked at 126 boys for every 100 girls [The Wall Street Journal blog].
With the greatest imbalance occurring with very young children, the researchers say that China will be grappling with the problem for 20 years. The imbalance is expected to steadily worsen among people of childbearing age over the next two decades and could trigger a slew of social problems…. “If you’ve got highly sexed young men, there is a concern that they will all get together and, with high levels of testosterone, there may be a real risk, that they will go out and commit crimes” [AP], says study coauthor Therese Hesketh.
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The Gouldian finch female has a neat trick for maximizing her offspring’s chance of survival: If she mates with a male who is a poor match for her genetically, she increases the proportion of male chicks in the resulting brood. In a new study, researchers say they’ve found unprecedented evidence that these birds can exert control over the gender of their offspring.
The endangered finch, native to the northern savannahs of Australia, can have either a black or red head, and the two different “morphs” have significant genetic differences, lead researcher Sarah Pryke says. “Gouldian finches wear their genes on their head so it is easy for a female to assess the genetic suitability of the male,” she says [Australian Broadcasting Corporation]. The birds prefer to mate with males that have the same head coloring, as chicks from a mismatched mating – particularly the females – are weaker and more likely to die very early [BBC News].
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Beauty is in the eye of the beholder, and whether that beholding eye belongs to a man or a woman may determine how beauty is processed and understood in the brain, according to a small, preliminary study. Researchers asked 10 men and 10 women to decide which paintings and photographs they found beautiful, while brain scans revealed which parts of their brains were active while they examined each image. The results suggested that while both sexes use parts of the brain associated with spacial awareness to process beauty, men use an area associated with big-picture thinking, while women also use a region linked to local details.
All the volunteers showed increased activity in the parietal lobe when gazing at a landscape or urban scene that they found beautiful, but men used only the right lobe, while women used the lobes on both the left and right sides of the brain. The researchers suggest that this is because women are contextualising the information and thinking more about the details of what they are seeing, assessing the position of objects according broad categories, such as “above” or “below”, or “left” or “right”. The men, they say, are focussing on the overall image using a more precise form of mental mapping [BBC News]. Study coauthor Camilo Cela-Conde hypothesizes that these differences may be linked to the different roles played by men and women throughout our evolution.
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A small study suggests that men are better able to resist food cravings than women, which researchers say could partially explain why more women than men are obese, and why women are more prone to overeating when they’re under emotional stress. In a new brain-scan study, researchers flashed tasty food in front of men and women who hadn’t eaten anything in at least 17 hours. Both were told to fight their hunger, but only men showed a drop in activity in brain regions involved in emotion and motivation [CNN]. However, some researchers say that it’s risky to generalize based on a study with just 23 test subjects.
In the study, which will be published in Proceedings of the National Academy of Sciences, researchers engaged their volunteers in a somewhat torturous experiment. They first surveyed the volunteers about their favorite foods: Did they favor pizza, chocolate cake, burgers, or fried chicken? Then they were asked to fast overnight. When they returned to the lab the next day, the subjects got PET brain scans while being subjected to a barrage of craving-inducing stimuli. They looked at pictures of their favorite food, smelled its aroma wafting in from the next room, and even tasted it with cotton swabs placed on their tongues.
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Men who want to know if they’d make it as day traders on Wall Street just have to look down at the fingers, according to a new study. The longer their ring fingers are in relation to their pointer fingers, the more likely they are to have what it takes to make millions on the trading floor. Previous research has found that the digit ratio reflects how much testosterone an unborn baby was exposed to in the womb. Those exposed to high levels of the hormone are more sensitive as adults to testosterone that creates feelings of confidence and encourages risk-taking, said study author John Coates [Bloomberg].
Coates has previously shown that traders who register the highest levels of testosterone in the morning make the most money through the course of the day, and this new study adds to the earlier work by suggesting that their advantage may have been innate, not learned. Although it may come as no surprise that testosterone could be a big player in the mano-a-mano world of Wall Street, the research offers the best evidence yet of the hormone’s role in determining which would-be Masters of the Universe will thrive. It also supports the growing recognition that biology plays a role in complex human behaviors, and that financial choices in particular are often less rational than economists appreciated [Washington Post].
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