Tag: sex & gender

Scientists Confirm: Blood Test Can Tell A Fetus's Sex at Seven Weeks

By Valerie Ross | August 10, 2011 5:07 pm

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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CATEGORIZED UNDER: Health & Medicine

To Boldly Grow Where No Sperm Has Grown Before: in a Petri Dish

By Patrick Morgan | March 25, 2011 1:09 pm

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:

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

CATEGORIZED UNDER: Health & Medicine, Living World

Study: Overt Discrimination Not Driving the Underrepresentation of Women in Science

By Andrew Moseman | February 8, 2011 1:26 pm

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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CATEGORIZED UNDER: Mind & Brain

The Nation's Science Report Card Is Out, and It's Not Pretty

By Andrew Moseman | January 25, 2011 4:48 pm

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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CATEGORIZED UNDER: Mind & Brain

Women's Tears Dampen Men's Sex Drive, Study Says

By Eliza Strickland | January 7, 2011 3:47 pm

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

CATEGORIZED UNDER: Health & Medicine, Mind & Brain

Mice Two Dads: Scientists Create Mice With Two Genetic Fathers

By Andrew Moseman | December 9, 2010 11:16 am

mouseThis 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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CATEGORIZED UNDER: Living World

Genetic Switch Makes Female Mice Try to Mate With Other Females

By Joseph Calamia | July 9, 2010 12:17 pm

PCWmice1Geneticists 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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CATEGORIZED UNDER: Living World, Mind & Brain

Does a Dose of Testosterone Make Trusting Women More Skeptical?

By Andrew Moseman | May 24, 2010 5:44 pm

face-collageAll 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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CATEGORIZED UNDER: Health & Medicine, Mind & Brain

Obama to Hospitals: Grant Visiting Rights to Gay Couples

By Andrew Moseman | April 16, 2010 9:26 am

Hospital emergencyLast 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

CATEGORIZED UNDER: Health & Medicine

Monkey Schoolmarms: Vervet Monkeys Learn Better From Female Teachers

By Andrew Moseman | March 17, 2010 11:39 am

VervetmonkeysWhen 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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CATEGORIZED UNDER: Living World, Mind & Brain
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