I consider the implications for brane-world scenarios of the rather robust
quantum-gravity expectation that there should be a quantum minimum limit on
the uncertainty of all physical length scales. In order to illustrate the
possible significance of this issue, I observe that, according to a plausib
le estimate, the quantum limit on the length scales that characterize the b
ulk geometry could affect severely the phenomenology of a recently-proposed
brane world scenario. (C) 2000 Elsevier Science B.V. All rights reserved.