They'll get sued immediately by everyone who is denied a job following a genetic screen.
There's a reason companies who require a physical or medical history (usually done to find pre existing conditions to protect against future workman's comp claims) do it after the job offer has been extended (it's risky to rescind an offer for no reason by the way) - if they did it before, every applicant with a disability (and their pro-bono lawyers taking a slam dunk case) who did not get the job would sue.