Bost's intention was to point out that they would not have a need for prenatal coverage at this point in their lives, and therefore men or women of a certain age should not have to pay for it. Still, his statement illustrates how difficult it is to create segmented risk pools for coverage specific to women and men. How do you determine where to draw the lines to have enough people in segmented risk pools, and in the insurance market overall, to keep costs affordable for everyone? And how do you do so fairly? That's the essence of the debate on Capitol Hill.

There are essentially two schools of thoughts as it relates to how to best structure health care: a broad pooling of health care risks across the entire insured population (generally championed by Democrats), versus more segmented pooling of health care risk (as generally supported by Republicans) among those who are sick or in need of specific types of expensive care, such as for pregnancy. There are winners and losers under both scenarios, and shades of gray between the two philosophies.