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Older siblings may be good for something after all. Infants whose mothers have been pregnant previously may have more active immune systems that protect them against asthma and hay fever, according to a paper in the June issue of Allergy. Researchers have noted a positive relationship between older siblings and allergies since at least 1989, when a study following British children for 23 years found that the more older siblings a child has, the less likely she or he will be allergic to airborne particles like dust and pollen. But exactly how older siblings boost younger sibling health has continued to flummox scientists. (Jacewicz, 6/22)

The vast majority of babies who experienced sudden unexpected infant death in Wisconsin during 2013 and 2014 were exposed to multiple risks for unsafe sleep, according to a report released Wednesday by Keeping Kids Alive in Wisconsin. During that two-year period, 119 babies died of SUID, which is the death of an infant less than 12 months old that occurs suddenly and unexpectedly and whose cause is not immediately obvious before an investigation. Though a disproportionate number of African-American babies died, SUID claimed the lives of children of all ethnicities in 33 of Wisconsin's 72 counties, according to the report. (Stephenson, 6/22)

President Barack Obama has signed into law the first overhaul of toxic chemical rules in 40 years. Obama is joined at a White House signing ceremony by lawmakers from both parties who supported the bill. He says for the first time in U.S. history, the country will be able to regulate chemicals effectively. (Lederman, 6/22)