It’s been all over the news lately that a Massachusetts General Hospital researcher, Jonathan Tilly, is claiming that contrary to the common belief that women are born with a set number of eggs in their ovaries, we may instead be equipped with “egg stem cells� that continue to develop into eggs as we grow and age. The science behind how Tilly is proving his claim is as basic as simple addition and subtraction and as otherworldly as glowing green mice.

First, the addition and subtraction. For more than half a century, the prevailing wisdom has been that baby girls are born with about a million immature eggs, or oocytes, apiece. Once they reach puberty, they shed about a thousand matured eggs per month (though in each cycle, only one egg goes into the fallopian tubes to be fertilized). Tilly actually counted the number of egg cells shed by mice, and in 2004 showed there were simply too many to allow the mice to remain fertile throughout their reproductive lives. His conclusion? Something was making more egg cells. That something turned out to be fetal germ cells, which in a fetus develops into either sperm or eggs, depending on the mouse’s gender.

READ MORE

A new study published in the journal Genome Research may hold clues to why we humans have much more prolonged childhoods than other critters. Researchers comparing the brains of humans, chimpanzees and macaques found that genes in the prefrontal cortex, a region of the brain which governs social behavior, delay of gratification and reasoning ability, express themselves differently in humans than in the other animals.

The major difference is pace. In humans, the genes, which control the development and function of the synapses between neurons, are highly active from just after birth until age five; in the chimps and birds, activity begins to tail off soon after birth. Further research showed that while the number of synapses in chimps and macaques peaked shortly after birth, human brains didn’t top out until age four. “Humans have much more time to form synaptic connections,� says lead researcher Phillipp Khaitovich. More synapses mean more brainpower. Even when researchers took into account humans’ longer life spans and generally slower rate of maturation, the different pattern of gene expression was clear.

Neurologist Eric Courchesne of UCAL-San Diego noted that the new study fits well with his research into autism. The brains of autistic children, he says, grow more quickly than normal—leaving them with fewer experiences to draw from in forming vital synaptic connections. The slower the brain wires up, the better, the study seems to say.

Eyebrows arched late last year when research published in the American Journal of Clinical Nutrition linked childhood obesity to being born by cesarean section. Scientists used those findings to theorize that not being exposed to certain bacteria during the voyage through the birth canal could cause kids’ immune systems to develop in ways that cause them to become overweight. Since so many American kids—30 percent—are being born via C-sections these days, researchers thought perhaps they were onto a piece of the childhood-obesity puzzle.

Not so fast.

A new review of the previous Brazilian research has shown that its authors failed to take into consideration such factors as family income, birth weight and the mother’s weight. Once those factors were accounted for, “the relationship between obesity and cesarean sections disappears,� according to Fernando Barros, who reanalyzed the data with a colleague. Barros said while there are other risks to cesarean sections, and that women should try to avoid those that are medically unnecessary, they won’t cause your offspring to be fat.

It’s been a matter of fierce debate on college campuses and in hipster homes for decades: Is smoking the occasional joint any better or worse for you than smoking the occasional cigarette? The Journal of the American Medical Association just published the results of a big fat study that says … it’s not!

Smoking (and inhaling) marijuana on a casual basis had no adverse effects on the pulmonary systems of the 5,000 lucky study subjects; in fact, many actually experienced improved lung functioning. Cigarette smoking, as I’m sure you’re more than aware, causes impaired lung function.

Scientists followed the pot smokers for 20 years and determined that smoking a joint a week for seven years doesn’t hurt lung function. On the downside, smoking a joint a day for a decade did cause a loss in lung capacity.

So the scientists urged moderation. Of course, they would.

Are you addicted to Action News? A Fox News aficionado? Guess what? It’s making you fatalistic. That’s right: The more tragic house fires, big traffic snarl-ups and heartwarming rescues of kittens you’re exposed to, the more likely you are to shrug your shoulders about fighting cancer, according to an analysis of data by scientists from Cornell University and Ohio State.

Chronic local-news viewers are less likely to take active steps to avoid cancer—like quitting smoking or eating more veggies—and more likely to view the disease as an inescapable, unavoidable, randomly dispersed doom, like a lightning strike. Why should this be so? The scientists theorize that in its desperation to boost ratings, local news presents so many possible cancer threats—bras, coffee, deodorant, microwaves, hot tea, mouthwash—that viewers throw up their hands under the constant bombardment, concluding that life itself causes cancer and nothing they do to stave it off can matter.

Which is probably true, but then, Melissa Magee is the bomb.