You might not have read that bill, the Patient Protection and Affordable Care Act, now codified at Pub.L. 111-148, 124 Stat. 119; and, that goes into effect in stages from July 1, 2010 through 2014.
A genetic predisposition is not a preexisting condition - it is a predisposition that may or may not result in the manifestation of the disease (you might get hit by a car, die in a war or avoid a BMI over 1.2 and prevent the predisposition to type II Diabetes from manifesting itself despite the genetic predisposition).
As a result I suggested that the insurance industry could (and, I'd bet money on this) determine that a pre-pre-existing condition - the genetic predisposition of a healthy individual - would be grounds to deny coverage.
The Patient Protection and Affordable Care Act is silent as to genetic predisposition - and as such, there is nothing precluding the industry from implementing this pattern of exclusion from coverage. RTFL