A developing human egg.
What’s the News: Since the 1950s, it’s been generally accepted that women are born with all the eggs they will ever have. One gets doled out with each menstrual cycle, and when they run out, you get menopause. But a smattering of papers over the last decade or so have indicated that that dogma might be incorrect: scientists found cells in the ovarian tissue of female mice that appear capable of producing new eggs. Now, working with donated tissue, researchers have found similar cells in human ovaries.
Headlines hyping the find have been spreading across the web, and we feel compelled to point out that this paper doesn’t mean that we will be able to grow fresh new eggs in Petri dishes, and it doesn’t prove that in real, live women these cells actually mature into eggs that can develop into offspring. It does, however, provide an interesting chance to see whether egg production by these cells can be jump-started using drugs.
The researchers chose to examine the sperm of crickets, because, as with humans, you can get samples of it without having the male come into contact with a female first.
What’s the News: You might already know that sperm, which can survive for only a few hours when exposed to the outside world, can live for several days in women after ejaculation. But did you know that an ant queen can fertilize her eggs with sperm she’s stored for up to 30 years? And that organisms as diverse as birds, reptiles, and insects can hang onto sperm and keep it fresh for days, weeks, or months?
Scientists studying this ability have been trying to figure out how females do it, and in a recent paper, researchers put forth evidence showing that the ladies may be arresting the aging process, by slowing down sperms’ metabolism.
What’s the News: The world’s population is projected to reach 7 billion this October and continue climbing, reaching 10.1 billion by the end of the 21st century, says an official United Nations report (PDF) released earlier this week. This is a significant departure from earlier projections that said the population would peak at just over 9 billion, then level off and even slightly decline.
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:
Not So Fast:
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