We all need mirrors to remind ourselves who we are. I'm no different.

Perusing the New York Times, I came across an article called "Is Bicycling Bad For Your Bones?"  Studies have shown a correlation between bicycling and brittle bones.  The bone density of 32 male, competitive bike riders, most in their late 20s and early 30s, was compared to that of age-matched controls, men who were active but not competitive athletes. Bone scans showed that almost all of the cyclists had significantly less bone density in the spine than the control group. Some of the racers, young men in their 20s, had osteopenia in their spines, a medical condition only one step below full-blown osteoporosis.

Interesting, to be sure, but I think you'd have to do an awful lot of cycling to have any ill effects.