I think as aProgDir alluded to, there are ample possibilities to resolve this issue. People can schedule their pregnancies or rotations to avoid having the birth/post-birth period fall during an exceptionally busy rotation. Many programs have research blocks that are well-suited for this. Or, perhaps the best solution would be offer to make-up the extra calls taken by their co-residents during the period they were out. My program, and I assume most programs, routinely make this a requirement when people take vacation for conferences or interviews.
I have no objection to women wanting to bond with their children. As you can probably infer from my posts, I'm pretty bitter about the lack of time I was able to spend with my kids shortly after they were born, and I still struggle with the limitations in time I can spend with them now. I never complained (at least anywhere other than SDN), because I made a choice on what to do with my life and I realized that came with the requirement for sacrifice.
What spins me up (and I think prompted the OP to start this thread in the first place), is that there are a subset of residents who genuinely believe that they have no obligation to consider anyone other than themselves in this process. That has second and third order effects, one of which is more nights where I have to say goodnight to my girls on the phone, instead of in person. And that sucks, because I would like to be a better parent than I am. They have a legal right to behave that way, but that doesn't make it moral, and certainly shouldn't stop anyone from pointing out that it is selfish and wrong.