I've gotta respond to CG's comments. He wrote: "But don't you think a woman that isn't pregnant is more valuable to an employer than one that is?" and "shouldn't women who choose to forgo pregnancy to focus on their career reap some reward (better job/pay) for the sacrifice they make?"
ABSOLUTELY NOT. Not only should men and women be paid equally for the same work, but parents and childless adults should also be paid equally for the same work. To "forgo pregnancy" does not necessarily mean you are going to be better or more productive at your job than someone with kids. In my field (biological sciences) I know male and female professors with children who manage to teach, publish, and get grants funded at the same (or even higher) rate and quality as professors without kids. So why would you pay them differently? Sure, it is true that there are scientist-parents who may have a brief "hole" in their publication record because of those 3 months they took for paid paternity/maternity leave. Unfortunately, this may affect their ability to get tenure or get grants funded (but fortunately many institutions are becoming more understanding of this). However, it should in no way whatsoever affect their salary!
In academic interviews it is against most institution's policies to ask if a candidate is married, has kids, is planning to have kids, etc. These policies are in place precisely because of the attitude you revealed in your comments in the earlier post. You cannot discriminate against someone based on these factors! And this is why it is best for an institution (or any place of employment) to have equal paternity/maternity leave policies - whether they hire a man or a woman, the possibility that that person will take parental leave is the same. You cannot decide against the woman because "she's a woman of childbearing age, so she'll probably take maternity leave". And actually, you cannot discriminate against men of childbearing age for the same reason either. I can understand the perspective of an employer who is short-staffed and needs someone to work full-time immediately with no extended leave on the horizon. But that employer has to realize that the possibility of extended leave is always there and is unpredictable. You never know if and when a employee will get cancer, have an accident, etc. and need an extended leave of absence. This is why you just have to hire the best candidate for the job and not discriminate based on perceived likelihood that a person will take parental, sick, or disability leave. Actually, I know a woman who, in the few years after landing her tenure-track position, had both cancer and a baby, and has still managed to stay at the top of her field.
All that being said, sure, it is possible that parenthood takes its toll on a person to the extent that their job performance suffers. But this is just one of many factors that can affect a person's job performance (divorce, chronic illness, depression, etc.) And that's why the only factors that should determine someone's salary or whether or not they get hired are their resume and job performance NOT their gender or family status.
In regard to the comment that a woman who isn't pregnant is more valuable than one who is, I look at my own place of employment. I am NO MORE VALUABLE to my employer than the two female teaching fellows currently expecting babies, or the male teaching fellow whose wife just gave birth last week (congratulations Jon and Celia!). Our supervisors at Duke University evaluate us only according to how well we do our jobs, not whether or not we take parental leave, an option open to all of us teaching fellows. It is unfortunate that not all employers practice such non-discrimination, and even more unfortunate that there are politicians do not support this mindset.