Because of the limitations of the study, it can't be concluded that tight underwear causes infertility.
But if you're trying for a baby, it can't hurt to try switching to boxers.
Other ways men can increase their chances of conceiving include moderating their alcohol consumption, stopping smoking, exercising regularly, and having a healthy, balanced diet.
This study alone doesn't explain the potential role of irisin.
The research did find that restoring irisin in Alzheimer's mice, including by daily swimming, can boost memory and nerve connections.
But we don't know that the same effects would be seen if people with Alzheimer's were given an exercise programme, for example.
We also don't know if any attempt to increase irisin levels through drug-based treatments (as some in the UK media suggested) would be either effective or safe, as no studies have been carried out in people at this stage.
Obese people who were metabolically healthy – the "fat but fit" – had a 28% higher heart disease risk than their normal weight, metabolically healthy counterparts.
There is no evidence that people exposed to the viral genetic material went on to develop an infection. That said, the researchers' suggestion that people should be encouraged to use alcohol hand disinfectant before and after security checks, to minimise the risk of infection, is sensible advice.
However the connections between diet, lifestyle and cancer outcomes are complex, and while the researchers attempted to adjust their results for other factors, we cannot say with certainty that energy dense foods increase your cancer risk.
The analysis was limited to postmenopausal women and did not consider drink intake, such as sugary drinks and alcohol, which can also be high in calories.
Limitations aside, there is a robust body of existing evidence that shows that regular consumption of sugary drinks can increase the risk of a range of health conditions, from tooth decay, to diabetes, to heart attacks and stroke.
If you are a night owl, there's no need to panic about the study. The usual rules about a healthy lifestyle – including getting sufficient sleep, at whatever time you choose to get it – still apply.
This study supports earlier studies that the MMR vaccine has no link with the risk of autism.
It follows a 2014 review that pooled the results of 10 observational studies on childhood vaccine and found no evidence of any link between the MMR vaccine and autism.
The strength of this study is that it follows a large number of children. This makes the findings more reliable when assessing a fairly rare outcome like autism, and reduces the possibility that the findings are down to chance.
This study finds very little hard evidence supporting the beneficial effect of vitamin D on neurodegenerative diseases.
That said, it's still a useful piece of research as it demonstrates the need for further studies in this area.
So, should people wanting to lose weight try to avoid PFAS? That would be difficult, and we don't know whether it would help. We don't know what levels of PFAS chemicals people in the UK have in their bodies. We don't know whether using non-stick cookware, or avoiding food packaging made using PFAS chemicals, would reduce PFAS levels in the body. Without this information, attempting to avoid PFAS chemicals does not seem practical or advisable.
While the conclusions – that children need time to work things out for themselves – may be correct (at least for some children), headlines blaming mothers for children's difficulties at school can be discouraging and unhelpful.
The research shows that joint injections of relaxin at high or repeated doses may prevent the build-up of scar tissue in the joint.
But it's currently not certain whether this could lead to a safe and effective new treatment for humans.
The study involved rats who'd had a surgical procedure to restrict their range of limb movement.
This is not necessarily the same as a person who's developed frozen shoulder after an injury or for an unknown reason.
This large study demonstrates that differences between men and women in the quantity and distribution of body fat not only lead to differences in body shape between women and men, but also may have implications for the risk of having a heart attack in later life.
But there are limitations.
Open access. Letter. Imo conducted a systematic literature review of research on the prevalence of burnout among UK medical doctors, arriving at the conclusion that the prevalence of burnout in this population is ‘worryingly high’. Problematically, it turns out that such a conclusion cannot be drawn in view of the state of burnout research. Indeed, there are no clinically valid, commonly shared diagnostic criteria for burnout.2,3
What the research actually shows is that many people from both urban and rural populations in the UK were poor, had little food and were likely to be malnourished. Many relied on white bread, potatoes and some vegetables, with a little meat or milk if they could get it.
There's no new evidence that these people were healthier than the average UK citizen living tody.