If anything, this weakens the researchers’ argument. It suggests lacking the genetic defect—rather than having it—makes suffering a herniated disk more likely.

If anything, this weakens the researchers’ argument. It implies having the genetic defect doesn’t make the likelihood of suffering a herniated disk all that high.

This implies a stronger correlation between the genetic defect and herniated disks. It’s more evidence that people with the defective gene tend to suffer herniated disks.

This weakens the researchers’ argument. It suggests the findings were not replicable, raising the possibility the researchers’ study was anomalous or poorly designed.

This weakens the researchers’ argument. It implies a different genetic or behavioral factor, other than the genetic defect in question, is likely responsible for the increased likelihood of herniated disks.