A recent study indicates that boys who swam in indoor chlorinated pools had concentrations of inhibin B (a testicular hormone biomarker) and total testosterone about 20 percent lower than those of boys who swam in a pool disinfected with copper–silver ionization. Those who swam in the chlorinated pool were also more likely to have abnormally low concentrations of these hormones. The research consisted of almost 400 primarily white boys, ages 14-18. Study authors, Alfred Bernard and Marc Nickmilder compared serum levels of several testicular hormone biomarkers between the two groups. They suggest that chlorine disinfection byproducts may cause the hormone variations. Read more...