LongGone said:
The same reason your tax dollars support your public schools even if you don't have children. The whole premise of healthcare is that everyone pays into the system.
But you don't have a "system," really. You have a bunch of private insurance providers offering health insurance and a law that says you must purchase a policy from one of them.
I live in a country with a single-payer "system." That which is medically necessary is covered. With respect to maternal care, that means routine prenatal visits and delivery. On the other hand, it doesn't include birth control, nor should it, since birth control is not medically necessary. If Canadians, say Roman Catholics, were compelled to subsidize contraception against their consciences, I would be in their corner just as I would be the Little Sisters of the Poor or Hobby Lobby.
My taxes pay to keep everyone eligible healthy. That is fair. They also pay to give everyone a basic public education. That also is fair. I shouldn't have to pay for someone's university tuition, though, and neither should I have to fund medical unnecessary health services like birth control.