What’s the News: A blood test can reliably tell a mother-to-be whether to expect a boy or girl as early as seven weeks into pregnancy, according to a new analysis published today in the Journal of the American Medical Association. The test can distinguish the sex of a fetus up to three months earlier than an ultrasound can, and doesn’t carry the slight risk of miscarriage that accompanies invasive tests such as amniocentesis.

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What’s the News: For the first time in medical history, scientists have successfully grown mouse sperm in a laboratory. As Northwestern University cell biologist Erwin Goldberg told New Scientist, “People have been trying to do this for years.” It’s hoped that being able to grow sperm outside the testes will lead to improved fertility treatments for men.

How the Heck:

• The concept is simple: Combine the right dosage of chemicals that will provide nourishment to testes in a petri dish. Actually finding the magic amount is a tedious process of trial and error.
• First, the team genetically engineered mice “so that a protein only present in fully grown sperm would fluoresce green.”
• Next, the scientists extracted germ cells (which produce sperm) from the newborn mice testes, and put them in a bath of agarose gel, fetal bovine serum, testosterone, and other chemicals.
• After about a month, they discovered that virtually half of the lab-grown sperm were glowing, indicating that they were fully grown.
• They then used in vitro fertilization to impregnate female mice, who eventually gave birth to fertile mice themselves.

Context:

• Past attempts at lab-grown sperm weren’t very successful. Many of the sperm cells from a  2006 study, for example, died before developing fully.
• Ed Yong has written about sperm, including the barbed sperm of the flatworm and the sperm wars between ants and bees.
• 80beats has covered how plastics decrease sperm counts, the secret of the sperm’s wild dash, and the shared 600-million-year-old sperm gene between humans, fish, and flies.

Not So Fast:

• The researchers developed offspring using only 100 sperm cells; doctors would like to see “millions if possible” to make successful fertility treatments in humans.
• Scientists may have observed “healthy and reproductively competent offspring,” but they don’t delve into the possible long-term side effects of creating people from sperm developed off the traditional route. In vitro sperm creation could be compared to IVF, a technique that leads to greater risk of diabetes and some other conditions. Researchers still aren’t sure why this is, though they have made some headway, discovering that the DNA of IVF-babies actually differs from other children.

Next Up: This technique still needs to be proved in humans, and if it is, it could have wide-ranging effects. For example, in the future, doctors might be able to extract testicular tissue from young boys—who haven’t yet developed mature sperm—and then grow sperm in the lab. Or for infertile men, doctors could extract germ cells, produce sperm, and then find out what’s wrong with them.

Reference: “In vitro production of functional sperm in cultured neonatal mouse testes” Takuya Sato et al. doi:10.1038/nature09850

Image: Wikimedia Commons / Bobjgalindo

In the continuing debate about how to make the career playing field more level for women in science, much of the attention has been focused on eliminating outright sexism in publishing and hiring. For a study published in this week’s Proceedings of the National Academy of Sciences, however, researchers looking into the causes of the lingering gender gap for women in math-intensive sciences suggest that it’s not outright discrimination that’s holding women back.

A 2008 survey of US universities by the National Science Foundation revealed that less than 30% of PhDs in the physical sciences were awarded to women. Higher up the ranks, women make up only about 10% of full professorships in physics-related disciplines. Yet when psychologists Stephen Ceci and Wendy Williams of Cornell University in Ithaca, New York, sifted through 20 years of research, they found little evidence of continued gender bias in journal reviewers, granting agencies or hiring committees. [Nature]

Instead, Ceci and Williams say, external and social factors—some matters of choice, some not—are the major ones hindering women in science today. Those factors include the much-discussed, such as the fact that a mother with young kids is still expected to stay on the fast tenure track, and the less-obvious, such as caring for aging parents or following a spouse who gets a job in a different city.

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This evening, according to early reports, President Obama will spend part of his State of the Union Address addressing the United States’ “competitiveness.” But ahead of the national pep talk, the Department of Education brought the mood down a notch. The latest results from a federal test called the National Assessment of Educational Progress were released today, and the “Nation’s Report Card” doles out some depressingly low grades for American students’ understanding of basic science.

A third of the nation’s fourth-graders, 30 percent of eighth-graders and 21 percent of 12th-graders are performing at or above the proficient level in science…. Fourth-graders considered proficient are able to recognize that gravitational force constantly affects an object, while advanced students can design an investigation comparing two types of bird food. Proficient 12th-graders are able to evaluate two methods to control an invasive animal species; advanced students can recognize a nuclear fission reaction. [Bloomberg]

At the other end of the spectrum, 28 percent of the 4th graders failed to show a basic understanding of science, and that number was up to 40 percent for high school seniors. That troubles Alan Friedman, a member of the board that oversees the test:

“I’m at least as concerned, maybe even more, about the large number who fall at the low end,” Friedman said. “Advanced is advanced. But basic is really basic. It doesn’t even mean a complete understanding of the most simple fundamentals.” [AP]

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From Ed Yong:

In an Israeli laboratory, Shani Gelstein is harvesting a woman’s tears. The volunteer is watching the end of the boxing film The Champ. As she weeps, she holds a vial under her eyes to capture the fresh drops. This might seem ghoulish, but Gelstein has used the collected tears to understand why people cry during emotional times. She thinks they’re a chemical signal.

Gelstein used several different techniques to show that the smell of a woman’s emotional tears could reduce a man’s sexual arousal. The men never actually saw anyone cry, and they didn’t know about what they were smelling. Even so, their sniffs reduced their testosterone levels and they lowered the activity in parts of their brain involved in sexual desire.

The small study had men smell both women’s tears and saline that had dripped down women’s cheeks, and measured the men’s reactions. The fascinating (if preliminary) results suggest new possible reasons why we cry at emotional times–read the rest of the story at Not Exactly Rocket Science.

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Image: Science / AAAS

This week in bizarre new forms of mammal reproduction: mice who have genetic material from two fathers but nary a mother, the next step in a progression of scientific efforts to get more creative with sex and reproduction.

“It has been a weird project, but we wanted to see if it could be done” in mice, says Richard Behringer, lead author of the study and a developmental geneticist at M.D. Anderson in Houston. [Wall Street Journal]

Weird, and also complex: The process requires several generations and some creative genetic trickery. To make it happen, Behringer’s team started with a single male mouse. Let’s call him Fred. Scientists took cells from Fred and transformed them into a line of induced pluripotent stem cells, which can grow into any kind of cell in the body. Normally, of course, a male’s sex chromosomes are X and Y. But when the researchers created these stem cells, some of them—about 1 percent—lost the Y chromosome through ordinary mistakes that happen in cell division.

Thus, the scientists had a batch of Fred-derived stem cells that had no Y, and thus were labeled XO cells. The next step was to take ordinary mice blastocysts—early stage embryos that had been conceived in the traditional fashion—and inject the XO cells into them. When this XO-injected embryo was implanted into a normal female mouse, she gave birth to offspring called chimera—what we call animals with two or more genetically distinct populations of cells. In this case the mouse possessed, in addition to the normal cells from its mother and father, some XO cells derived from Fred.

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Geneticists have found a way to alter the sexual preference of lab mice. When they bred mice that had one gene deleted, the females declined male companions and preferred instead to court other females, according to a study published yesterday in BMC Genetics. But whether these results have any implications for humans is still far from clear.

Chankyu Park and his team at the Korea Advanced Institute of Science and Technology deleted the female’s fucose mutarotase gene and, as a result, changed the brain’s exposure to enzymes that control brain development.

The gene, fucose mutarotase (FucM), is responsible for the release of an enzyme by the same name, and seems to cause developmental changes in brain regions that control reproductive behaviors. The mice without the enzyme would refuse to let males mount them, and instead tried to copulate with other females. [AOL News]

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All it takes for some people to be a little less trusting of their fellow humans is a little more testosterone, according to a new study in the Proceedings of the National Academy of Sciences.

Researchers led by Jack van Honk of the Netherlands used a sample of 24 women in their study. The team showed photos of 150 strangers’ faces to the women and asked them to rate the faces for trustworthiness, using a scale from -100 to +100. The scores women gave after receiving a placebo became their “baseline” score. The women also completed a trustworthiness survey after being given an increase in testosterone instead of placebo (they weren’t told when they received which).

Scientists found that women were not so easily taken in by a stranger’s face after receiving a dose of the hormone…. Women who appeared the most trusting after receiving the “dummy” placebo reduced their scores by an average of 10 points when their testosterone was boosted [Press Association].

Why? The researchers point to the social advantages testosterone can confer:

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Last night, President Obama issued a memo that will change hospital visitation rights around the country. The administration will draft new rules declaring that any hospital participating in the government’s Medicare and Medicaid programs—which is most of them—will no longer be allowed to bar visitors that patients desire to have access to them.

This has been a particular hardship for gay Americans, who have been turned away from visiting sick loved ones because of policies that allow visiting rights solely to spouses or family members. They aren’t the only ones, either, Obama argues. He cited widows or widowers without children, members of religious orders as examples of people who have been unable to choose the people they want to be at their side [Reuters].

The changes won’t take effect right away. The Department of Health and Human Services must draft the new rules, then put them in place and police them. But in addition to expanding visitation rights, the order also requires that documents granting power of attorney and healthcare proxies be honored, regardless of sexual orientation. The language could apply to unmarried heterosexual couples too [Los Angeles Times]. You can read Obama’s memo here.

The President was particularly inspired by the case of a Florida couple, Janice Langbehn and Lisa Pond. When Pond suffered an aneurysm, Langbehn was denied visiting access at the hospital, despite the fact that she carried power-of-attorney and the couple had adopted four children. Pond died before Langbehn was allowed access. On Thursday night, Mr. Obama called her from Air Force One to say that he had been moved by her case. “I was so humbled that he would know Lisa’s name and know our story,” Ms. Langbehn said in a telephone interview. “He apologized for how we were treated. For the last three years, that’s what I’ve been asking the hospital to do” [The New York Times].

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Image: iStockphoto

When vervet monkeys play follow the leader, they prefer to follow a female. That was the conclusion of Erica van de Waal, whose lengthy study of these primates in South Africa will be published this week in the Proceedings of the Royal Society B. When her team presented them with a tricky contraption they had to open to reach a tasty snack, the monkeys learned better if they watched a female from their group demonstrate the solution rather than a male.

Seeking some answers to how social learning works in monkeys, van de Waal and her colleagues headed to Loskop Dam Nature Reserve. It took four months, they say, just to acclimate the wild animals to the presence of humans. Once the monkeys were comfortable having scientists around, Van de Waal gave each group a wooden box containing a slice of apple. To get to the apple, the monkeys had to either pull open the door at one end or slide aside a door at the other. Half the box was painted black to differentiate the two ends [ScienceNOW].

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The technical way to explain this odd-looking fowl is that it’s “gynandromorphous.” But if you just want to call it “one seriously confused chicken,” that works, too.

For a new study in Nature, Michael Clinton and colleagues investigated a few of these half-male, half-female chickens they obtained from chicken farms. Gynandropmorphs show up now and then not just in chickens, but also in parrots, pigeons, and some other kinds of animals. But scientists weren’t sure how the mix-up happens, since the standard idea for sex differentiation is that the sex hormones released by the gonads either masculinize or feminize the embryo. Clinton’s team discovered that bird cells don’t need to be programmed by hormones. Instead they are inherently male or female, and remain so even if they end up mixed together in the same chicken [BBC News].

The researchers had first assumed that the half-and-half chickens followed the hormone pattern, and that they were females with some sort of chromosomal problem on the male side (the lighter half of the bird in the image, which also sports a large wattle, sturdy breast musculature, and a leg spur on its male side). Instead, they found the chickens to be almost perfectly split between male and female. The hen half was, for the most part, made up of normal female cells with female chromosomes, whereas the cockerel side contained mostly normal male cells with male chromosomes [Nature News].

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You are what you eat, and perhaps in some ways, what your mother ate. Back in 2003, Cheryl Rosenfeld’s team found that the diet they fed to pregnant mice caused a “striking variation” in the sex ratios of the offspring: High fat favored males, low fat favored females. Now Rosenfeld has a new study in the Proceedings of the National Academy of Sciences that says the mother’s diet can also affect the very way genes are expressed in the placenta.

To figure this out, Rosenfeld’s team studied the placentas attached to fetal mice 12 and a half days after conception, when the mice were midway through gestation but had yet to produce sex hormones like estrogen or testosterone (those can also alter gene expression, which would have confounded the study). They found that gene activity in the placentas differed significantly depending on whether the mom was fed a high- or low-fat diet. The biggest differences were found when comparing the high- and low-fat placentas linked to female fetal mice, suggesting that placentas nourishing females do a better job of responding to diet—and potentially protecting the fetus from harmful ingredients—than do those connected to males [ScienceNOW]. Specifically, of the 700 genes that they saw behave differently between the sexes, 651 were expressed more in females than males. In all, their study saw changes in the expression of nearly 2,000 genes.

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Male animals often use their horns to fight over females, but at least one species’ females use their horns to fight over excrement.

The species, no surprise, is the dung beetle. Unlike many of the animals we usually associate with elaborate horns, antlers, or other head weaponry—in which the male has the most impressive set—dung beetle females have horns that put the male version to shame. The reason, says a new study in the Proceedings of the Royal Society B, is that females must battle one another for that precious manure. Nicola Watson and Leigh Simmons of the University of Western Australia, Perth, pitted female dung beetles (Onthophagus sagittarius) against each other in a race for dung – a valuable resource that provides nutrients for their eggs. Matched for body size, females with bigger horns managed to collect more dung and so provide better for their offspring [New Scientist].

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Does your first- or second-grade daughter have trouble with math? Her anxiety could be stemming not just from a genuine fear of number crunching but also, a new study indicates, from an anxious female math teacher.

The study (pdf) published in the Proceedings of the National Academy of Sciences shows that if a female teacher is anxious about math, she tends to pass on that anxiety to her female students. This can make the female students believe they aren’t hard-wired for math like the boys, and cause them to shy away from fully flexing and developing their mathematical muscles.

The findings are the product of a year-long study on 17 first-and second-grade teachers and 52 boys and 65 girls who were their students [Science Daily]. Researchers recruited the female teachers from a Midwestern school district and assessed their level of math anxiety. They also gave math tests to 117 of these teachers’ students and jotted down their beliefs about math and gender at the beginning and end of the year. By the end of the year, the more anxious teachers were about their own math skills, the more likely their female students – but not the boys – were to agree that “boys are good at math and girls are good at reading” [AP].

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Don’t count out the Y chromosome just yet. Far from being in a state of decay, as some studies have suggested, a new study in Nature says the male chromosome in humans is actually evolving at a furious pace.

Study leader David Page of MIT sequenced the human Y chromosome back in 2003, and in the new study his team compares it to the male chromosome of chimpanzees. The scientists expected the two sequences to look very similar. However, while human and chimp DNA generally differ by less than 2 per cent, more than 30 per cent of the Y chromosome differed between the two species [The Times].

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