health to those as simple as the pleasure of having blue skies and clean water (Grodsky, 2005).
Policies regarding who should bear the costs of behavioral choices and environmental exposures are mixed as well. In the individual health insurance market, people who smoke or who work in hazardous jobs pay higher premiums. At the same time, both the federal and many state governments regulate the extent to which insurers can use some types of information, particularly information about genetic predispositions, in their underwriting. Employers are concerned with health care costs because they pay higher premiums if their workers have large claims. Over the last 20 years, the ability of employers to exclude workers who may have high health care costs has been limited by laws such as the Americans with Disabilities Act (ADA) (42 U.S.C.A. §§ 12101 et seq. (2006)), which forbids discrimination against workers with disabilities so long as they can fulfill the essential elements of the job with reasonable accommodation, and cases such as Automobile Workers v. Johnson Controls (499 U.S. 187 111 S.Ct. 1196, 113 L.Ed.2d 158 (1991)), which held that Johnson Controls could not exclude women from the potentially fetotoxic workplace. Thus, Terri Seargent, who was essentially asymptomatic, successfully claimed that she was fired because of the costs of enzyme replacement for her A1AT deficiency (Clayton, 2001).
This body of law, however, recently has been undercut by cases such as Chevron v. Echazabal (536 U.S. 73, 122 S.Ct. 2045, 153 L.Ed.2d 82 (2002)), in which the Supreme Court upheld regulations issued under the ADA that permitted employers to refuse to hire workers whose underlying medical conditions make them more likely to be made ill by the toxic workplace. Finally, although society often tries to encourage its members to avoid risky behavior, it has chosen not to require people to bear all of the consequences of their actions. Instead, reflecting a belief that a civil society should provide basic care for its citizens, our health care system provides a substantial, if spotty, safety net against catastrophic illness for many of its members, even when those diseases result in part from personal behaviors.
Expressed another way, risks to individual health of whatever sort—genetic, behavioral, or social—raise a set of common questions, as illustrated below. For these purposes, we assume that a threshold level of scientific validity has been met demonstrating that a particular factor influences disease risk.3