As Head of the MIT Physics Department, I categorically reject his conclusion that stereotype threat and implicit bias play no significant role in holding back women in the hard sciences. They do; I have seen them at work.I recommend you go read the whole article, it's quite a good read.
Our very own CSWA has taken on the issue of implicit bias and stereotype threat at recent meetings, including plenty of data on the subjects. But, as Isis notes, Tierney does enough cherry-picking to make a pie. After all, Tierney himself demonstrates the bias that women face, by blaming our lack of advancement on our soft maternal natures, rather than realizing that the assumption that we care more about work-family balance than our careers is an example of the kind of bias we face.
Finally, I just wanted to note that I was a little surprised that I didn't see more of an uproar on the blogosphere on Tierney's articles than I did. After all, he did "dare" us to confront him. But I think many of us are suffering from outrage fatigue. After all, it's the same tired arguments over and over again. So I think it's worth taking Zuska's point to heart: Tierney's audience is not us, women in science and our supporters. Rather, he is lobbying against a specific piece of legislation that would help us. And right there is the reason that we should continue to fight, no matter how tired we become of the battle.