HMM: Pyrethroid pesticide exposure appears to speed puberty in boys. This says it’s because pyrethroids boost testosterone. But aren’t testosterone levels in adult men — who presumably would be exposed, too — falling? “Liu’s research team found that a 10 percent increase in 3-PBA was associated with a 4 percent increase in the boys’ levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Both these hormones spur production of testosterone in males.” This is in China, of course, so it may not apply here to the same degree.