A reader writes:

If, as Hanna Rosin says, the wage gap gets huge after 4-5 years after the first child is born, can't an explanation be that that's when the women see that their kids are growing and won't stop, that the ideals of their youth are not relevant in the face of the deep emotional attachment they are feeling towards her child? I have always seen myself as a huge feminist, and was completely blindsided by the depth of my need to be with my daughter. It is a basic hunger; I feel a nearly physical attachment to her. On top of that, she needs me to be with her, to hang out, to talk, to just *be* together. In the face of that, how can spreadsheets and after-work socializing compete?

I pity/don't understand people who never feel this with their kids. I know that before having kids, I felt a deep love for my cat – and afterwards, I realized that I had no idea how deep deep was.

Another writes:

No wage gap exists for me at the moment because I am a union member in a blue-collar industry.

I've seen not only my own paychecks, but occasionally my coworkers', when our semi-conscientious payroll company screws up and mails the wrong check. I've also seen the labor bills we submit, and I know how fast our business moves, substituting one person for another in last-minute jobsite changes. Not only is it written in our constitution and by-laws, it would be horrendously difficult. I'm sure gender discrimination could exist, but it would take a level of organized conspiracy so determined and widespread as to be unlikely, at least in my local.

We women make the same wage for the same job because we are deemed interchangeable. Our contracted employers do not specify gender; they assume that the personnel we supply for each job are competent to do the job and earn the same rate. If they object to the quality of the work, they take that up with us on a case-by-case basis – individual problems are addressed individually, but not via wage changes. If they don't like your work you don't get asked again, which is brutal but in some ways fair.

It is true that women are usually not offered certain better-paying jobs because their gender is considered a proxy for their ability to lift, and those positions require lifting that is heavier than average for men, under safety conditions requiring a cushion of certainty. I won't consider that discrimination until I see a woman clearly able to do the job turned aside. Haven't yet. (I suppose there's a conversation worth having about structural coercion and why the load an average worker should be expected to carry should be based on the average man's lifting ability rather than the average woman's … wouldn't it be worthwhile to consider the relatively weaker gender a baseline for, ha, manual labor? Why not make our loads manageable and theirs easy and expand both the workforce and its safety in one move? I suspect it would require more people to give a damn than they do.)

By no means do I deem unions perfect constructs. In fact, they are a last resort, a signifier of human indecency, to be resorted to when employers value individual employees so low that collective action is the only leverage possible to force employers to treat us well. Why else do Wal*Mart and Amazon so routinely crush union formation? If the GOP's revulsion for unions succeeds in damaging not only public-sector unions but (as is their clear intent) private-sector unions as well, Hanna Rosin's projections are going to need some updating. The ground women have won is not yet solid, for more reasons than the so-called "women's issues."