The GOP may die or become a fringe party before it nominates a woman. Collins, Murkowski, or Snowe? Either wins -- as a Democrat after defection or expulsion from the GOP.
In present day politics there is no well-known credible woman who may become president other then Sarah Palin. That doesn't mean that the Republicans will die out if a woman is nominated someday. I admit, the Democrats have a longer list of candidates who may become president in modern day politics, but it doesn't mean any of them will win or ever run.