Artifact:

Foreruner =/= Human

Sorry, no relation (genetically)

If their wasn't a a genetical relationship (no matter how slight) how would they know how to use forerunner equipment, and how can they use some equipment while the covenant couldn't?

Also the main reason spartans were about to control most covenant vehicles because the covenant tech is reversed from forerunner tech. In an essence they "Remembered" how to work that wraith in Fall Of reach.