Discovered: Dads who snooze with baby have lower testosterone; popular kids more likely light up; reruns boost mental health; is acupuncture safe? 

Baby-daddy nap lowers testosterone levels. Dads like this guy who join their babies for nap time exhibit lower testosterone levels on average, which is actually a good thing according to new a study in PLoS ONE. The researchers involved examined the testosterone levels of 362 Filipino fathers in the same age range. Dads who slept next to their babies exhibited a third less testosterone than they did previously, compared to those sleeping alone. Scientists have already known that disturbances in a man's sleep cycle can lead to a drop in testosterone. But in this new study, they find a new correlation to baby-daddy sleep proximity and the hormone. The testosterone drop is probably positive, scientists say, cutting down on a man's tendency to be aggressive and unsympathetic toward the baby and mother. [Scientific American]

Watch some TV reruns to restore sanity. When life starts to get hectic, sometimes the only thing that will bring you serenity now is a Seinfeld rerun. At least that's the suggestion in new studies from the University at Buffalo's Jaye Derrick. She finds that re-watching an episode of a favorite TV show helped restore people's determination to tackle difficult tasks. "People have a limited pool of these valuable mental resources," says Derrick. "When they use them on a task, they use up some of this limited resource. Therefore, they have less willpower and self-control for the next task." She found that TV reruns were particularly helpful for replenishing those resources. "When you watch a favorite re-run, you typically don't have to use any effort to control what you are thinking, saying or doing. You are not exerting the mental energy required for self-control or willpower," Derrick says. "At the same time, you are enjoying your 'interaction,' with the TV show's characters, and this activity restores your energy." [University at Buffalo]

Pinpointing acupuncture risks. Acupuncture is often touted by new age types as a holistic alternative to Western medicine's nasty side-effects. But the first ever study of UK acupuncture clinics' adverse effects finds that the ancient Chinese therapy might incur some harm too. National Patient Safety Agency investigators studied reports of nasty acupuncture effects from NHS clinics between 2009 to 2011, and concluded that 10% of all treatments had some unwanted outcome. Cases ranged from mild dizziness to more severe harm, such as lung collapse. Edzard Ernst of the University of Exeter concludes, "Clearly this is not a highly risky treatment. But acupuncturists are adamant that it is devoid of risk, and that is not the case." Many European national health care systems fund the therapy, and the U.S. government has been considering funding acupuncture through Medicare. [New Scientist]

All the cool kids are doing it. Maybe those scare-tactic D.A.R.E. lectures were right—popular kids do peer pressure each other into smoking more than their unpopular peers. A survey of 1,950 students in Los Angeles high schools found that kids with higher social capital were more likely to smoke. The USC Keck School of Medicine's Thomas Valente led the study, which finds that one quarter of 9th graders have smoked, and the number is significantly higher for those cited more often on others students' list of five best friends. "Smoking is still being marketed as a sign of maturity," says Valente. Peer pressure "was consistently and strongly associated with individual smoking," he says. [Los Angeles Times]