Assuming that's the case, who cares? Why all the hand wringing? One downside I see is the lack of a "woman's perspective," which, while admittedly important in many fields, seems mostly irrelevant in a field where stuff either works or it doesn't. The other is a lack of interest in the field overall, but it seems a constant source of debate (see any H1B visa thread) as to whether we have a shortage or a glut of qualified workers.
[1] This shouldn't be read as a position I'm strongly committed to.
EDIT: Criticisms of this post thus far are mostly along the lines of a) a woman's perspective matters more than I give it credit for and b) "works or doesn't" is too simplistic. Fair enough. I admit my argument wasn't particularly nuanced (purposefully), hence the "devil's advocate" label. Questions I would ask are: wrt point a), is this something we can empirically validate? Or should we just assume any gender imbalance is inherently problematic? I'm not necessarily against the latter view, but I'd like to see it addressed explicitly.