British doctors claim to have made an important step toward completing the first womb transplant. They say they have solved the problem of keeping the blood flowing to the transplanted uterus so that a pregnancy can be carried to term in the recipient. Womb transplants, if proven successful in humans, would offer an alternative to surrogacy or adoption for women whose own wombs have been damaged by diseases such as cervical cancer. Around 15,000 women of childbearing age are currently living with a womb that does not work or were born without one [Guardian]. The research was presented at the American Society for Reproductive Medicine (ASRM) conference in Atlanta.
However, the technique has only been demonstrated in rabbits, a far cry from successfully completing a womb transplant in humans. Using a “vascular patch technique” major blood vessels including the aorta were connected. Two of the five rabbits lived to 10 months and dissection after death showed the womb had stayed healthy [BBC News]. The research team has yet to show that the new wombs can actually support a pregnancy, which leaves some scientists skeptical that the procedure is actually an advancement.
Ethicists, medics and feminists have long argued as to whether infertility is a disease or a cultural phenomenon born of a society where women feel they have no value if they cannot reproduce. But illness or otherwise, it is not a fatal disease, and the suggestion that women could undergo major transplant surgery to fulfill their desire for a child may prompt unease [BBC News]. A woman who received the transplant would have to take drugs to suppress her immune system to prevent her body from rejecting the foreign organ. To avoid taking the drugs for life, the uterus would likely be removed again after the desired babies had been born.
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Look into the future and see the women of tomorrow! A new study predicts that future women will be a tad shorter, heavier, and more fertile—that is, if the women who are currently most successful at producing children are any indication. The team studied 2238 women who had passed menopause and so completed their reproductive lives…[and] tested whether a woman’s height, weight, blood pressure, cholesterol or other traits correlated with the number of children she had borne. They controlled for changes due to social and cultural factors to calculate how strongly natural selection is shaping these traits [New Scientist].
Their results show that shorter, heavier women tend to have more children, as do women with lower blood pressure and cholesterol. If the mothers pass on these traits for 10 generations, the average woman in 2409 will be 2 centimetres shorter and 1 kilogram [about 2 pounds] heavier than she is today. She will bear her first child about 5 months earlier and enter menopause 10 months later [New Scientist]. A two-centimeter decrease over 400 years may be a modest change, but the researchers say it’s evolution in action. The study will be published in Proceedings of the National Academy of Sciences.
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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
Two researchers have reviewed the body of research on the effects of birth control pills on both women and men’s perceptions of attractiveness, and have come to some provocative conclusions. Women on the pill are less attracted to hyper-masculine men, they found, and don’t show the typical propensity towards men who are genetically dissimilar from themselves. In addition, women on the pill may lack the attractiveness edge that’s associated with ovulation, the study found.
An alarmist, tabloid-esque summary of the findings might read like this: Pill-taking women aren’t hotties, and they pick girlie men who are likely to give them ugly babies. But of course, there’s a lot more complexity to the findings. The contraceptive pill alters monthly fluctuations in hormones associated with the menstrual cycle, mimicking the more stable hormonal conditions associated with pregnancy [New Scientist]. While mounting evidence suggests that having one’s hormonal levels smoothed out in this way alters some of the laws of attraction between men and women, scientists hasten to add that hormones aren’t everything.
The new study (pdf), published in Trends in Ecology and Evolution, looked first at research that’s been conducted on women’s preferences for men. Women who aren’t on the pill have shown a preference for certain types of men while they’re ovulating: they prefer men with more traditionally masculine facial features, and have also been shown to prefer the smell of men who are genetically dissimilar (which in humanity’s earlier days, when inbreeding was a danger, would have been an advantage). Women on the pill don’t show these same preferences. But many would argue that personality is a far better way to choose a life partner than what they smell like. One recent study involving speed-dating experiments suggested that although women might say they prefer the scent of men with dissimilar immune systems, this doesn’t correspond with the men they actually chose to go out with [New Scientist].
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Forget, for a moment, all those fancy geoengineering schemes that would alter the face of the planet in an attempt to reduce global warming‘s impact. Population scientists argue that a cheaper and simpler strategy is to hand out birth control to those who want it–especially to people in the developing world, where birth rates are booming.
The world’s population is projected to jump to 9 billion by 2050, with more than 90 percent of that growth coming from developing countries…. In countries with access to condoms and other contraceptives, average family sizes tend to fall significantly within a generation. Until recently, many U.S.-funded health programs did not pay for or encourage condom use in poor countries, even to fight diseases such as AIDS [AP].
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Oil and gas companies looking for deposits offshore have touted their equipment as environmentally friendly. However, new research suggests that blue whales are having a hard time hearing each other over the seismic blasting that the search entails. Research has discovered that whales forced to compete with the seismic testing work, which involves bouncing sound waves off the sea bed, markedly increase the number of times they repeat the same calls [The Times].
The study, published in Biology Letters, was conducted in Canada’s St. Lawrence Estuary, and is the first report of whales increasing their calls in response to underwater noise. Researchers believe that the whales are repeating the calls simply because other whales can’t hear them, and they’re having trouble gathering to feed and mate.
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Over the past four years, a controversy has erupted over whether to routinely give girls the new vaccine against the human papillomavirus (HPV), a sexually transmitted virus that can cause genital warts and cervical cancer. Now we can have the debate all over again–but this time, with boys. An advisory panel of the Food and Drug Administration has recommended that the vaccine be made available for boys as well. While boys are obviously not at risk for cervical cancer, HPV can give them genital warts and, in very rare cases, can lead to anal or penile cancer.
The pharmaceutical giant Merck makes the first HPV vaccine available in the United States, Gardasil, which is considered most effective when given to young people who aren’t yet sexually active and therefore haven’t yet encountered the virus. But analyst Tim Anderson says that the regime of three shots over six months may deter some customers. “You are asking a healthy teen to come to the doctor three times in six months,” Mr. Anderson said…. “Pretty much no healthy teen would ever do that, let alone to come back and get a shot” [The New York Times]. It may be a particularly hard sell because most cases of genital warts clear up naturally, and because anal and penile cancers are so rare–each year they’re diagnosed in about 2,100 and 1,300 American men respectively.
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Image: flickr / lu_lu
These cute little macaque monkeys may have gotten their fluffy brown fur from their father, their big eyes from their mother, and their good health from… their other mother.
The scientific advance heralded in a new paper in Nature is essentially procedural: Researchers have figured out how to make an embryo that does not carry the mitochondrial DNA of its mother but that of another female instead, which could prevent diseases that are caused by inherited defects in this genetic material. But the study’s immediate impact comes from the ethical questions it raises. “With this you have potentially three genetic parents,” said [bioethics expert] David Magnus…. “This will create the potential for legal and social conflicts.” [Washington Post].
While more than 99 percent of an embryo’s DNA comes from the union of a sperm cell with the nucleus inside a female egg, the other 1 percent is found in other structures outside the egg’s nucleus–the mitochondria, the cellular power plants that produce chemical energy. This mitochondrial DNA is inherited only from the mother, but in the new study on rhesus macaques researchers monkeyed with that biological truism.
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Gravity appears to be crucial to the development of mouse embryos, implying that mammalian reproduction in zero gravity may be trickier than scientists thought. Researchers have bred animals from sea urchins to frogs in space. When they tried to artificially fertilize mouse eggs in a machine that simulates a gravity-free environment, fertilization took place normally, suggesting that microgravity hadn’t harmed the sperm. But as the embryos continued to develop inside the clinostat, many developed problems. Their cells had trouble dividing and maturing [Wired].
Scientists speculate the reason that the mouse embryos developed less successfully than previous animals is because mammalian embryonic development is more sensitive and complicated than that of other types of animals. “Sustaining life beyond Earth either on space stations or on other planets will require a clear understanding of how the space environment affects key phases of mammalian reproduction” [Wired], the researchers wrote in their paper, published in the journal PLoS ONE.
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In the first experiment linking cognitive ability to reproductive success, researchers found that the male bowerbirds with the best problem-solving capabilities also mated the most often, according to a study published in the journal Animal Behaviour.
The Australian bowerbird is known for its elaborate courtship behavior. During breeding season, males build a special platform, or bower, on the forest floor to lure females, and they decorate it with rare objects such as blue feathers and shiny bits of glass. They accompany this with varied vocalizations, hopping, and tail-bobbing [ScienceNOW Daily News]. To evaluate which males had the best problem-solving abilities, scientists placed a red object in the birds’ bowers–a color the birds disdain. In one experiment, three red objects were placed in the bower and covered by clear plastic that the bird had to take off in order to remove the noxious items. In the next, the red object was securely nailed to the nest, so the only way to make it less visible was to cover it with leaves and twigs.
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The yeast that causes thrush–an infection of the mouth and tongue–can reproduce homosexually, offering a clue as to why the yeast-caused infection can be so difficult to treat.
When mating, the yeast known as Candida albicans can take one of two sexes: a or alpha. When researchers mixed the two types of yeast, they found that yeast cells of the same sex mated, although not very often, according to the study published in Nature. And they increased this homosexual mingling by boost[ing] a pheromone secreted by “a” cells that draws same-sex cells together [New Scientist]..
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Orchids have a clever way of attracting pollinators: By releasing the same pheromones honeybees give off to communicate with other hive-members in times of emergency.
[T]he bees are the favorite food of the larvae of Vespa hornets…[so] when the orchid Dendrobium sinense sends out these false alarms, the hornets pounce on the petals, thinking they’ll bring a bee dinner home to the kids [Scientific American]. The hornets leave hungry, but they help out the orchids in the process.
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Birth rates have decreased by about 2 percent in 2008, the first year since the beginning of the decade that rates did not increase, according to statistics from the National Center for Health Statistics. Many experts speculate that this drop is due to the recession. Still, birth rate statistics have not yet been finalized, and some believe that a decrease in immigration could account for the decrease in births.
As any parent knows, children are expensive, so in a shaky economy, it makes sense that fewer people would be having them. “It’s the recession,” said [sociologist] Andrew Hacker… “Children are the most expensive item in every family’s budget, especially given all the gear kids expect today. So it’s a good place to cut back when you’re uncertain about the future” [New York Times]. Perhaps not coincidentally, the two states with the largest decrease in births–California and Florida–are also the ones that faced the biggest problems due to the housing crisis.
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Circumcising men who are infected with HIV does not protect their female partners from the deadly virus, researchers have found. The Uganda-based study was stopped early due to “futility,” the researchers wrote in a study published in The Lancet, when it became clear that the women were not benefiting. The outcome was disappointing because circumcision has been shown to drastically reduce infection rates in men. But the researchers said that wide-scale circumcision is so effective in protecting men that [it] will still likely benefit women indirectly by reducing circulation of the virus in general [Reuters].
In 2007, the World Health Organization concluded that circumcising males reduced female-to-male transmission of the HIV virus by about 60 percent. The foreskin of the penis, which is removed during circumcision, is rich in cells that are particularly easy for the virus to infect. The theory is that removing this source of vulnerable cells makes infection more difficult [Reuters].
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To obtain a steady supply of unfertilized human eggs for medical research, New York’s Empire State Stem Cell Board recently authorized paying women to donate their eggs. The decision has set off a new round of discussion about whether paying for eggs is ethical. The board agreed that women can receive up to $10,000 for donating eggs, a painful and sometimes risky process…. Proponents say compensating women for their eggs is necessary for research, and point out that women who give their eggs for fertility purposes are already paid. Others worry that the practice will commodify the human body and lead to the exploitation of women in financial need [The New York Times].
At the annual meeting of the International Society for Stem Cell Research this week, British researcher Alison Murdoch described a less controversial “egg sharing” program that has met with success. Women struggling to conceive can obtain IVF at a discounted rate, in exchange for donating some of their eggs for research…. In 2008, Murdoch’s team had 191 enquiries from interested women and ended up obtaining 199 eggs from 32 couples. “We are getting donors and we are getting eggs,” says Murdoch. The team is using the eggs in experiments into “therapeutic cloning”, which could ultimately produce stem cells matched to individual patients [New Scientist].
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