The blood tests measure a protein called PSA that sometimes signals prostate cancer is brewing. That level can be high for other reasons, but doctors usually order the invasive biopsy to be sure.
Researchers say there are men whose PSA levels are naturally higher due to genetic reasons. Testing for this variant could save some from undergoing an unnecessary biopsy.
The full report is in the journal Science Translational Medicine.
A spokesman with the American Cancer Society says the genetic approach makes sense but more research is needed.