September 13th, 2013
06:15 PM ET
Here's a roundup of five medical studies published this week that might give you new insights into your health, mind and body. Remember, correlation is not causation - so if a study finds a connection between two things, it doesn't mean that one causes the other.
Verbal development linked to drinking
Researchers found that, in twin pairs, the twin who began speaking earlier in life had a higher likelihood of more frequent drinking than his or her same-aged sibling at some point in adolescence. The twin who learned to read first had a higher probability of drinking or intoxication in young adulthood.
This does not suggest that verbal skills cause drinking behaviors. Peer associations are related to both, says lead study author Antti Latvala. It's likely a different phenomenon than the association between poorer cognitive skills and the risk for severe problems related to drinking.
"Even though better verbal skills may predict more drinking in adolescence, this finding needs to be seen in the context of such drinking being very common and almost normative among adolescents," Latvala said in an e-mail.
Living mice get stem cells
Stem cell science generally takes place outside living beings, so it was exciting this week when scientists announced they had created stem cells in mice. Specifically, they reprogrammed adult mouse cells so they would act as embryonic stem cells would.
The next step will be regenerating specific types of cells.
“We have demonstrated reprogramming,” Manuel Serrano, a cancer researcher at the Spanish National Cancer Research Centre in Madrid, told Nature.com. “Now we have to show regeneration.”
Scientists find left-handed genes
Not to say that genes have hands, but there is a gene called PCSK6 that is associated with relative hand skill. Researchers saw strong correlations between this variant of this gene and left- vs. right-handedness, based on data from 3,300 participants.
Researchers found that many genetic variants contribute to handedness, and some of them are in genes involved in body asymmetry. When PCSK6 is disrupted in mice, for instance, their organs may develop on the wrong side of the body.
New Scientist reports: "This may help explain why left-handedness still persists in a right-dominated world: so many genes contribute to the trait that it is impossible to silence them all."
Estrogen contributes to men's aging woes
It has been long thought that diminishing testosterone among aging men is responsible for such phenomena as low sex drive and belly weight gain. But a new study in the New England Journal of Medicine suggests that estrogen, a female sex hormone, also plays an important role.
Scientists say lowered levels of estrogen as men age are also to blame for common complaints of aging, such as diminished libido. Estrogen is involved with fat accumulation, while testosterone levels are associated with muscle size and strength, study authors say. Both hormones regulate sexual function.
"In light of what the Women's Health Initiative discovered about the unexpected effects of estrogen replacement therapy in women, we need a Men's Health Initiative to investigate those questions before large-scale testosterone replacement can be recommended," study author Dr. Joel Finkelstein of Massachusetts General Hospital said in a news release.
Smaller testicles, more-involved dads?
Get ready for a laugh: Scientists conducted a study suggesting that fathers with smaller testicles have a greater likelihood of being nurturing to their children.
"Fathers' testicular volume and testosterone levels were inversely related to parental investment," the study says, "and testes volume was inversely correlated with nurturing-related brain activity when viewing pictures of their own child."
This does not mean that fathers with large testicles are bad parents, of course. CNN's Josh Levs has the full scoop on this ballsy study.
About this blog
Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.