I wonder if this is more a symptom of having few women in the field of computer science / software engineering [1] than a lack of women who want to be founders [2]. It isn't too surprising when you consider only a small percentage of people in computer science decide to become founders, and then a small percentage of that pool ends up being women.

[1] I am assuming that most people in startups are computer science types. Which isn't entirely (or very) accurate. Certainly when you add in fields like design and business/marketing this really changes.

[2] Of course, being a founder doesn't require restricting oneself to starting a technical business.