I think this issue is more about Yeoman than Genesis, but I thought I'd post it nonetheless.
Ran into this
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "generator-evolve" "generator-genesis-wordpress"
...
npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules/generator-evolve/node_modules/balanced-match'
when trying to Update your generators through Yeoman.
