With two adults it's usually a male and a female who engage in activities that create a new life, and there's a cost for that new life even before it is born.

Or are they thinking that two people will dislike each other enough to shoot or stab or beat on each other thus increasing the medical costs?

The site may be imperfect but at least it tries to offer some comparative info. I've never seen another site that does the same ... not in such an easy to understand format anyways.