So I got measured at 21% with calipers, which seems about right. I did the math, and to get to 17 or 18% I need to lose about 7 lbs of fat.

For those who have low bf, is it genetic? Do you have to work to maintain that #?

All other things being equal, is the effort to get down to a "competative" bf worth it for racing, will 7 lbs alter my ability to climb? (Bikemomma, pink kona?)