An ethical quandary is emerging over custodianship of and access to DNA specimens and attached data, clinical and genetic, held in large disease cohort collections. The balance of patients’ rights and science/society's quest for broad open access must be resolved in order to realize the promise of gene association studies of complex human disease. A way forward may be to convene a colloquium of international medical and science organizations charged with developing global consensus guidance and ethical principles for access to and use of genomic biobanks.