Latest research: Arm moles predict melanoma risk; male and female hearts age differently, and the youngest/eldest/middle child personality trait is a myth

King's College London researchers have investigated a new method that could be used by GPs to quickly determine the number of moles on the entire body by counting the number found on a smaller "proxy" body area, such as an arm - thereby identifying more easily people at the highest risk of developing skin cancer. Skin cancer risk is thought to increase by 2-4 per cent per additional mole on the body. Using data from more than 3,500 white female  twins between January 1995 and December 2003, the scientists found that the count of moles on the right arm was most predictive of the total number on the whole body. Females with more than seven moles on their right arm had nine times the risk of having more than 50 on the whole body and those with more than 11 on their right arm were more likely to have more than 100 on their body in total, meaning they were at a higher risk of developing a melanoma. In males, the legs and the back area were also strongly associated with the total count.

Male and female hearts don't grow old the same way

A new analysis of MRI scans of the ageing hearts of nearly 3,000 adults shows significant differences in the way male and female hearts change over time. Researchers at Johns Hopkins University who led the study say the findings may shed light on different forms of heart failure seen in men and women that may require the development of gender-specific treatments. The study participants, aged 54 to 94 and without pre-existing heart disease, were tracked for 10 years. In both sexes, the main heart chamber, the left ventricle - which fills with and then forces out blood - gets smaller with time. As a result, less blood enters the heart and less gets pumped out to the rest of the body. The study reveals that in men, the heart muscle that encircles the chamber grows bigger and thicker with age, while in women, it retains its size or gets somewhat smaller. "Thicker heart muscle and smaller heart chamber volume both portend heightened risk of age-related heart failure but the gender variations we observed mean men and women may develop the disease for different reasons," says lead investigator Dr John Eng.

Birth order has only very small effects on personality

Firstborns are perfectionists, middle children develop a talent for diplomacy and last-borns are rebellious - or so the long-held birth order stereotypes go. But a new study by German researchers in Leipzig and Mainz that analysed central personality traits of more than 20,000 adults from Germany, the US and Britain have found that who we become only marginally correlates with our birth position among siblings. They found that central personality traits such as extraversion, emotional stability, agreeableness, and conscientiousness are not affected by birth-order position. Only regarding self-reported intellect were small effects found: firstborns were more likely to report a rich vocabulary and less difficulty understanding abstract ideas.