Men's Group

Differences in type of compensation (monetary vs nonmonetary) appear to make a difference in the career choices that men and women make; (men choose jobs based almost exclusively on monetary considerations, while women give weight to other factors - see the "work/life balance" thread).

... but this bias shows up as pay differential between various careers. I would expect a teacher with X education, with Y experience, working Z hours per year to pay the same regardless of gender, but not necessarily be the same as the pay rate for electricians. The fact that the teaching offers time off, family-friendly schedule and good benefits tends to attract women who express a preference for those non-monetary factors.

The 7% difference does take into account the difference in pay rate between teaching and electrical engineering... but not the tendency for men to negotiate for salary.

That said, there are probably some variations in pay rate for individual electrical engineers which reflect these preferences (one can take the EE job with the flexible schedule and the better insurance OR the one with higher pay rate.)