I grabbed a couple citations while I was there because I was also curious:
* http://onlinelibrary.wiley.com/doi/10.1111/1468-0432.00129/a... - "Although generalizations from student-based studies to the workplace is problematic, the results indicate that groups may be more effective when women outnumber or equal men, especially in complex management activities requiring extensive information management and processing, planning and decision-making over protracted periods."
* http://sgr.sagepub.com/content/27/1/79.short - "Overall, in this study, gender diversity facilitated task performance for a male-oriented task without sacrificing cohesion or at the expense of increased decision-making time." (From the full text of the paper, the last concluding sentence.)
So I'm not sure why you would assert:
> We all know that you can't provide any evidence to back this up
 I have no idea what they mean by this, but I'm going to guess "tech" would probably be classified as such.
>This study has four limitations. First, the sample comprised students only working within fictitious enterprises in hypothetical industries and, as such, may not represent what actually happens in reality.
>Second, the sample size was smaller than ideal.
>Third, ethnic minorities were not identified among group members ... non-European individuals were present, but comprised less than 10% of the total sample.
>Finally, no all-women groups were included within the study.
>The use of student subjects is problematic, however, they remain one of the few sets of participants who are readily accessible
And regarding the second study, I have no idea what that concluding sentence even means. Because in the discussion, the authors state:
>As expected the task was oriented toward males. Consequently, as the male gender ratio increased, decision quality improved. However, the lone-female teams outperformed the all-male teams.
Further the study is based on asking groups of undergraduates to carry out the winter survival task (i.e. if your plane crashed in a forest, rank these 12 items in order of importance for survival). It is beyond ridiculous to extrapolate anything from these results and apply it to group productivity in extremely technical professional fields.
> We all know that you can't provide any evidence to back this up. What is your agenda? Why do you think we are stupid?
The assertion you made is that there was no evidence to support pencilcode's assertion that gender diverse teams perform better. I believe this assertion is false, the top results of a cursory search that I made out of curiosity provided evidence which supported pencilcode's position.
However, I of course agree that two papers is hardly conclusive, so feel free to cite more studies if you want to start wading into the pool of evidence available to us on this topic.
They could have as well written "In a galaxy far far away...."