I continue to read conservative columnists/bloggers attacking the contraceptive mandate on the grounds that there's no such thing as a "free lunch". But of course, it's not free, because in order to get your "free" lunch (health insurance including contraception), you're giving up a similarly priced but worse lunch (health insurance without contraception) to get it, as previously discussed.
One of the better conservative arguments I've read on the subject was on The Health Care Blog. The author points out that "If insurers saved money handing out contraception for free in the first place, they would have started to hand it out for free years ago."
So why don't they? It has to do with how long a beneficiary is with a particular health insurer. I honestly had a lot of trouble finding a statistic for that, so let's look at the average time a worker spends working a particular job; I think it works as a stand-in given that most people get their insurance through their employer. This article from the Wall Street Journal estimates that the typical worker will spend 4.1 years.
With that fact in mind, a health insurance company doesn't give a shit about how expensive your health care will be 5 years from now. This undoubtedly skews the cost-benefit analysis of insurance companies on the question, if they don't have to worry about health costs for health care during school years for the children who result from their limited coverage. More generally, it's also why there are still health insurance companies that don't pay for other preventative measures like the HPV vaccine, or as I describe it to patients, the cervical cancer vaccine. If you're not the insurer that is responsible of paying for a lifetime of Pap smears and a possible bout of cancer, it's not in your interest to pay the hundreds of dollars to provide the HPV vaccine.
For an individual insurance company, giving free contraception might not make any sense, because they would probably lose money. But if every insurer does it, the costs throughout the entire system go down. This is why the ObamaCare mandate includes a requirement for contraception and other preventative services without a copay.