Mike Arrington says flat out that the reason why there aren't enough women in tech is because "not enough women want to become entrepreneurs." It's a question of motivation. This statement is easily falsifiable and I don't think any of the responses make even a meager attempt to do that.
Is there a disproportionately higher number of women-lead start-ups applying for venture funding and then not getting it? Since this is a question of motivation, even showing that a significantly higher percentage of women-lead start-ups fail would suggest that Mike Arrington is wrong.