Society's perception of women is not a legislative or political issue. And again, if they could bulldoze women into taking lower salaries, employers would be soliciting applications at women's colleges, and not calling men in for interviews. Unless there are practical reasons not to take advantage of women's cheaper rates...
The scientific accomplishments of today's society do allow one to counteract such biological differences, though, with contraception largely invalidating that argument. And further down the line, while basic biology permits only the mother to give birth and breastfeed, there's no biological reason why the father couldn't handle most or indeed all other aspects of raising children. Very likely the large majority of couples wouldn't even desire such a role-reversal, but some would, and why should society frown on that? And more might desire it if there was indeed more tolerance for it.
But the point is, when women DO chose to do the child thing, it adversely affects their earning power, which is where a lot of the pay gap comes into play. For single men and women, in the same jobs, with the same education and experience, there is no pay gap. On the other hand, married men make more than single men (not derive higher salaries from the same employer for the same job), and married women make less than single women, all other factors being equal.
The circumstances that result in women making less, are due to their own lifestyle choices, not bigotry. Unfortunately, recognition of these existing factors is now being referred to as bigotry. That Harry Potter chick alluded as much in her brain-grating UN speech, and I've seen women citing apocryphal & anecdotal employers who are reluctant to hire women out of fear they'll quit to have kids in a few years. Except a lot of them do. When my brother got a job at a cancer treatment facility, his supervisor said she was glad he was male in regards to one particular task on which she was training him, because the last four people she trained to do it got pregnant and left. How many times are you supposed to get bitten like that in the name of maintaining gender equality? As it happens, nurses are predominantly female, so it's not like my brother was undermining the sisters, but these are real practical problems.
I can recall similar issues when I was a supervisor at a retail store with 15 year old employees, and the limits on the work they could do, vs the cost-effectiveness of hiring them. At one point, we hired a girl who was a fantastic worker, and decided 15 year olds were not yet "ruined" by society or peer-pressure, and hired 3 more. It turned out that first girl was an outlier, and not at all typical of her age group. The experience with types of employees works both ways. I knew a couple of guys not long ago who were part-time dispatchers with my local police department, and when a full-time position opened up, they went for it. The officers were high on their chances, only for a young woman to be hired, both because the department was replacing a female in that position, and did not want to be accused of sexism in shoving her out, and because they assumed that the men would leave in a few years to try to become cops. Projections of employee career tracks work both ways.
Furthermore, if, as you point out, birth control etc negates the disadvantages women face, should they not have to own those choices, now that they ARE choices? No one MAKES her get pregnant, so why do employers have to accommodate that? Why is it acceptable to take time away from your job for one sort of irrelevant self-indulgence at not another? If a woman (or man, for that matter) can take off to have a baby and have her job held for her, not to mention get compensation for doing nothing, why can't another employer take off to work on his or her golf game? The latter is much more likely to be a source of networking opportunities, at least. There is no benefit to an employer to an employee breeding, as it will simply be additional competition for the employee's time, attention and priorities. If an employer refuses to embrace "family friendly" human resource policies, that should not be an occasion for lawsuits or picketing, they should just let the free-market and 13th Amendment drag that employer down.
That's a large part of the explanation to be sure, but not the whole of it - and they are intertwined, in the sense that over the long term women would start making difference lifestyle choices if society's views on women and gender roles evolved, and they could make higher wages.
And beyond that, you need some sort of proof that the gender priorities and behaviors are necessarily the result of socialization, rather than socialization simply following the trail blazed by biology, in much the same way biology dictated the inclusion of toilet facilities in structures intended to be occupied by humans for extended stretches of time.
Furthermore, the contentions about society shaping gender roles and expectations is a bit disingenuous in a time when you could never make a TV show or movie that negatively portrayed a women who prioritized her job & career over her children.
And on a related note, if ultimately managing society's view of women is more important in the long term, what do you do about birth control? While it does, in the short term, prevent maternity-related career disruptions, it also contributes to the sexual objectification of women, by divorcing sex from its most humanizing consequences. Not to mention, speaking of birth control, that equalizing the perception of parental and economic roles between the sexes should do away with the presumption of financial responsibility on the part of fathers, since "her body" and "her choice" were entirely responsible for the advent of his paternity, especially if he is not otherwise involved in her life.
That might be worth considering, since the thrust of Phyllis Schlafly's successful campaign to derail the ERA was that it could be used to impose traditionally male responsibilities on women.
It sounds plausible enough that that would be the case, but I'd have to agree with you that it's not something really worth bitching about - those women for whom the salesman's generalized assumption is appropriate, well, you can't blame him for trying to make more money, and those for whom it's not appropriate can just walk away.
But the problem with this stuff is that it's not simple complaints; in so many cases, it is being used to argue for legislation.
"Sometimes unhinged, sometimes unfair, always entertaining"
- The Crownless
“Tolerance is the virtue of the man without convictions.” GK Chesteron
Deus Vult!
