dejags. Yes, I think it could change over time. As you say, 100 years ago men were driven into a frenzy by the sight of bare ankles. There are societies in which women walk around bare-breasted - I'm thinking of African tribal societies, and aren't there also some cultures in the Pacific in which women don't cover up their top half?
I don't think men are incapable of distinguishing between breasts as baby-feeders and breasts as sexual objects - or, to put it another way, I think they are quite capable of seeing them fulfill both roles, and separating the roles in their own heads as necessary.
Also, as a feminist, I'm not comfortable with arguments that say: such-and-such a female characteristic is sexually arousing to men, therefore women must cover it up or take the consequences. It's the same argument behind head-covering and burkhas and all of that stuff with wot I strongly disagree. If men find such-and-such a characteristic arousing, well frankly they're just going to have to deal with it - particularly when it comes to something as fundamental and important as a baby. Every now and then I'll see a man who makes my heart beat faster, but it's my responsibility to stop myself jumping on him - or, indeed, staring so hard that it makes him uncomfortable.