Gender, Independence, and Authorship I have attended a few panels on applying to post-doctoral/junior faculty positions, and the topic of authorship and research direction always came up. All of the faculty on these panels noted that successful applicants needed to distinguish their research from their PI's by pursuing novel questions and publishing first-author papers. 

But the women faculty also noted that regardless of the novelty of a question, a woman coauthoring a paper with her PI (even if she is a first author) is seen as less independent than a man coauthoring a paper with his PI. Consequently, the suggestion was that women should pursue sole-author publications or publications with colleagues at similar or earlier stages of their career.

These panels included faculty from physics, chemistry, and anthropology, but I want to focus on the natural sciences. 

There are a few questions I have related to this advice. 


Does it happen? Is what these women faculty describe true? For those of you who have served on faculty/post-doc selection committees, have you seen the evaluations of comparative candidates differ according to their gender? 
Latino and Black applicants: There were no Latino or African-American faculty on these panels, but the reasons the women faculty gave for why women should go the extra mile in establishing independence seem to also apply to candidates from underrepresented groups. Have you seen evaluations differ according to whether candidates were from such groups? 
Establishing Independence without Sole-Authorship: Supposing at least one of the answers to the previous questions is in the affirmative: It is not always possible for young scientists to develop sufficiently independent projects that lead to sole-authorships. How else might a candidate demonstrate sufficient independence from her PI? Recommendation letters can conceivably convey the quality and independence of a candidate, but are there things the candidate can do herself? 


I recognize that the answers to these questions are likely opinion-based, but I am primarily looking for the opinions of stackexchange members in order to gauge whether the issue the women faculty cite is unique to my university.
Does it happen? Is what these women faculty describe true? For those
  of you who have served on faculty/post-doc selection committees, have
  you seen the evaluations of comparative candidates differ according to
  their gender?


Yes. This does happen. It is often hard to recognize - there's a degree of implicit bias at work all the time that's difficult to detect, because rare are applicants with genuinely comparative applications. It's easy to write off something one way or another - the prestige of the journals in question, the conclusions of the paper, etc. But I have, at times, seen it.


  Latino and Black applicants: There were no Latino or African-American
  faculty on these panels, but the reasons the women faculty gave for
  why women should go the extra mile in establishing independence seem
  to also apply to candidates from underrepresented groups. Have you
  seen evaluations differ according to whether candidates were from such
  groups?


While I encounter this less commonly because of the wide underrepresentation of these (and other) minoritized groups generally, I have seen it happen.


  How else might a candidate demonstrate sufficient independence from
  her PI? Recommendation letters can conceivably convey the quality and
  independence of a candidate, but are there things the candidate can do
  herself?


A couple things come to mind:


Being the PI on your own project. These may be small pilot grants or the like, no one expects you to land an R01 or the like. But it suggests some driving of your own research project.
Collaborations with not your PI. Your PI does not have to be on every paper you write, and it's possible to establish side projects etc. with other researchers. This occasionally has to be done with caution, due the the balancing of commitments, but it is possible.
If your job applications end up with a "Chalk Talk" where you outline your research agenda, nailing that. In my experience, this is where most candidates where I am, regardless of their gender, race or ethnicity, fail to establish their independence. You need to learn to tell the story of you the researcher, and how what you've done is, by and large, a logical arc into what you will do as an independent researcher.