A recent analysis by NIGMS staff has uncovered some promising results for women entering academic positions in the biomedical sciences. The study, which published today in the Proceedings of the National Academy of Sciences (PNAS), found that once men and women receive their first major NIH grant, their funding longevity is similar. The data contradict the common assumption that, across all career stages, women are at a large disadvantage compared to men.
The results of the analysis should be encouraging for women interested in becoming independent investigators, since the likelihood of sustaining NIH grant support may be better than commonly perceived. You can read the full study, “NIH Funding Longevity by Gender,” 
in the current edition of PNAS.
Interesting analysis!
The data are also consistent with several scenarios where women DO continue to face conscious and unconscious bias at all career stages.
For example, the women who make it through the very stringent bottleneck described (not only gaining a faculty position but also an R01) might be twice as skilled/brilliant/productive as their male counterparts but face bias that counteracts their excellence.
In fact, if we hypothesize that the pool of young women considering a career in science are as equally skilled as men, yet only the best of the women get to the career stage mentioned (2:1 outnumbered by men), it *must* be the case that continued bias exists for them. Otherwise, this 31% cohort of women would be expected to be 2:1 more successful than their male counterparts!
So there are (at least) two explanations for the observation that the best Nth percentile of women competes equally with the best Nthx2 percentile of men: women are inferior scientists or there is continued bias against them. Or some combination of both.
As we point out in the conclusion of our paper, there are many factors that affect the career trajectories of women and men differently. Addressing these factors was outside the scope of an analysis relying on grant records, but is an important topic to pursue. More study is needed to understand the cause of the initial imbalance in first time grantees, and any factors that could affect women and men differently at later career stages.