Men might enjoy revenge more than women, especially when it involves someone they dislike. Results of a study in the journal Nature showed that both men and women feel empathy toward people experiencing pain, but men in particular get pleasure if they have negative feelings toward them. Researchers asked 32 volunteers to play a financial game, four of whom were actors planted to play the game unfairly. Later, the researchers applied mild shocks to both fair and unfair players and studied brain scans of witnesses. Empathy-related areas of the brain reacted in both sexes, but when unfair players were shocked, the pleasure region of the brain was aroused in the men. Researchers say the findings suggest men have an evolutionary role in maintaining justice. (Nature, January 26, 2006)

Children exposed to pesticides may have a twofold risk of developing cancer. According to a French study published in Occupational and Environmental Medicine, infants and children exposed to indoor and outdoor insecticides and even shampoos for treating head lice had double the risk of developing leukemia compared with children who had no exposure. Researchers interviewed the mothers of 280 French children younger than 15 years who were diagnosed with leukemia between 1995 and 1999. When comparing these children with similar healthy children, the researchers found that mothers of children with cancer were more likely to have reported home insecticide use than mothers of healthy children. (Occup Environ Med, February 2006)

Don’t bother reaching for the cough syrup the next time you get a cold. New guidelines published in Chest advise eliminating the use of over-the-counter cough syrups to treat coughs and the common cold. Physicians say the common syrups are a waste of money, performing no better than sugar water. Americans spend an estimated $270 million a year on cough syrup. Although many types of cough syrup may help cold sufferers fall asleep, they contain drugs in such small doses that they are not effective. Instead of depending on cough suppressants, physicians say waiting out a cold is usually the best way to treat it. (Chest, January 2006 supplement)

Working the night shift? Exposure to blue light can help keep you awake. Research published in the journal Sleep shows that people exposed to blue light were able to stay alert at a time in the night during which people usually feel most sleepy. Researchers exposed volunteers to either blue or green light during a 6.5-hour night shift and found that people in the blue group had faster auditory reaction times, experienced fewer attentional failures, and reported feeling less sleepy than the other volunteers. Researchers believe the short wavelengths in blue light counteract the body’s natural desire to follow the circadian rhythm. However, they warn that misuse of the light can damage eyes, so exposure should be monitored. (Sleep, February 1, 2006)

A study published in the Proceedings of the National Academy of Sciences reported that boys born during stressful times live longer than those born during times of peace. Researchers used birth and death information from Sweden dating back to 1751 and found that males born during the most stressful times in history ended up living four months longer. Pregnant women are more likely to miscarry male fetuses (which are weaker than female fetuses) because of increased levels of cortisol produced by stress. Cortisol causes male fetuses to move in the womb, and those who are too weak to move often are miscarried. Researchers say that although fewer males are born during stressful times, their populations are stronger because the weak ones are lost earlier. (PNAS, January 31, 2006)

Obese men have an increased risk of death from prostate cancer, according to a study published in the Journal of Urology. Researchers reviewed the medical records of more than 1,400 men with cancer whose prostates were removed between 1988 and 2004. They found that biopsies of obese men sampled less of the total tissue because their prostates were larger. This makes it 20 to 25 percent harder for physicians to detect the cancer, increasing the risk of death by 20 to 35 percent for obese men. Researchers recommend that physicians perform rectal examinations and conduct laboratory testing that can help discover the presence of prostate cancer in these men. (J Urol, February 2006)