My daughter (18, y/o, CF, CFRD) began swimming competitively in 7th grade, lettered for all 4 years in high school, and plans on swimming in College starting this fall. I am sold on the benefits of aerobic exercise, and swimming does have significant benefits. However it does have risk - PA is ubiquitous in the environment, but no moreso in pools than elsewhere. A bigger issue may be asthma - swimmers have higher rates of asthma compared to non-swimmers. Of course we need to reasonably consider risk, but I also think we need to raise our kids to live life to the full, to be responsible and respectful, and to be as independent as reasonably possible.