Viagra isn't going to change the state of one's mind. Or if it does, Pfizer needs a new marketing campaign. ;)
The "men have dirty minds" characterization, though common, is inaccurate. Men and women have different sexualities - there is no "better" and no "worse". Women aren't morally superior just because they are somewhat less likely to find visual imagery sexually stimulating. Though admittedly it's easier for the priests, preachers, and politicians to impose guilt and sin taxes on visual imagery than on romance novels, so that characterization has been a handy fund-raising tool throughout history.
I agree there is some pretty steamy romance novels out there..But you are correct it is the visual imagery that is condemned because you can see it...Reading is what you see in your mind...