I live in a third city in Sweden, in a slice of time that the company needed to find someone and we do not pay competitive wages.
I’m sure we could find someone qualified eventually and if we paid enough, and we have had good female candidates at other times albeit for different roles than this one, however they didn’t want to relocate.
Context being what it is, it takes us roughly 2 years to hire a new person to our team because people don’t want to live where we are or accept the rates we pay.
If you can actually attract people to your company, then asking that you hire at least half women shouldn't be an issue; there are plenty of qualified women for any position. If you can't attract people to the job generally, I think any other factors would largely be noise versus the real problem.
Application rates of women for our studio borders 8%, and our previous hiring rate of women was 8%; with aggressive affirmative action policies (mostly around marketing and bringing in female code academies such as pinkprogramming[0]) we have increased this to 12%.
You don't specify /why/ the job is less attractive, I stipulated primarily two reasons:
1) Location.
2) Salary.
You might agree that moving 700+ people is a little untenable.
My argument about salary is, and very much playing devils advocate for HQ: "We don't really care who does the job as long as the job gets done, if we can pay a man less, we should hire a man".