Here's the issue: the office has only 1 restroom (for a staff of about 10). And women employees don't like that.
And they aren't unique in this challenge. Most of the office buildings have restrooms built as an afterthought, and even if they have multiple restrooms, even allocated as "Ladies" and "Gentlemen" (part of old colonial legacy) -- the allocations aren't honored all the time. So, a typical complaint across all women staff is the lack of clean, and more importantly, dedicated restroom facilities.
Now, I doubt if this is a key reason for the lack of female engineers -- but in a generally reserved culture, I'm bound to assume that the female employees don't discuss this issue as much with the management, and the management (usually male) doesn't think much of the issue either to actually take some actions. Maybe it's too trivial, not core to the business -- whatever, but it is an issue nevertheless. Maybe offshore locations plagued by high turnover problems can use this as a differentiator for retention.
I should point out that our offshore counterpart has a female president.