Straw man. By buying health insurance as a healthy young man you are essentially voluntarily taking on those costs.
It is not a question of whether she wants others to fit the bill for her medical expenses, but whether society as a whole decides to accept an amount of responsibility for the health of its people.
You are only voluntarily taking on those costs because of threats of violence against anyone who would give you the opportunity to purchase insurance without those costs.
Insurers have been completely willing to sell maternity-free insurance, at least until men with guns threatened violence against them for doing so. It's not exactly voluntary when threats of violence eliminate all competing alternatives.
It is not a question of whether she wants others to fit the bill for her medical expenses, but whether society as a whole decides to accept an amount of responsibility for the health of its people.