If you have watched television nature programs, you may have seen videos of lions attacking relatively easy game: animals which are very young, very old, sick or separated from the pack. Defenseless against the predatory lion, the young, old, sick and socially isolated are easy prey.
In my experience negotiating health care contracts- and studying the practices of health insurers - I observed similar corporate behaviors. Individual underwriting of pregnant women, in states such as Texas, resulted in their inability to obtain maternity coverage at a point when they needed it the most. Newborns with congenital diseases, which might cost millions of dollars in health care services, led to cost-shifting. Underwriting made those with significant (and sometimes insignificant) health histories unable to obtain insurance or to afford the insurance offered to them (one insurer representative claimed that the company represented had very few HMO members who were over the age of 24). And those, seeking individual health insurance policies, were offered coverage which only the very rich could afford.
Take a look at the article from Kaiser Health News, "Health Law's Individual Mandate, Essential Benefits Draw Headlines." You may find that my metaphor - of predation - is not far off base. The difference is that the insurers, their lobbyists and those in our government, whom their political contributions support, tread our nearby streets, state capitol hallways, and Congressional venues not far off jungles.