"Swimming in a chlorinated pool may increase your risk of developing cancer, suggest a new suite of studies, which identified more than 100 chemical byproducts in pools that use chlorine as a disinfectant.
The work is too preliminary to suggest that people should stop
swimming, said Manolis Kogevinas, an epidemiologist at the Center for
Research in Environmental Epidemiology in Barcelona. The studies were
small, and they found a rise in blood markers that have been associated
with cancer -- not a rise in cancer itself." Source: Discovery News