Do you mean real studies or lab studies, and what are your criteria of interest? In most Western countries larger corporations and the public sector would be covered by anti fuscrimination legislation since the 70s which would require some gender representation on every panel, so single sex panel research would be rarer or dated. 

Stephen,

Firstly thanks for answering,

You hit the nail on the head, although gender is less ambiguous then sex for readership purposes. Gender-anything is extremely politically sensitive in  the western world and other capitalist democracies, so much so, nobody is willing to talk about it. Despite how uncomfortable it is, it something that should be (re)evaluated.

In my field, gender effects, organizational/firm-HR policy and planning. From training, induction, staffing, to health and safety, job design, employee relations, labour standards and compensation, men get this treatment women get that. Recent events have made me concerned about the concept of fairness in 2015 and beyond; interviews are one example.   

At this point I refuse to give specific examples for the simple reason that they will be attacked no matter what or how they are presented, and the point of this question will be blurred and lost. Though, I will note some sort of due process (which would be my next question) needs to be in place to deal with gender-equality issues particularly before the baby boom generation retires.  (A few weak processes & practices exist, they need to go further, most seem to function on a contingency basis)

I was thinking focus groups would be a good place to start?

Hi Daryn

Focus groups could be used in a number of ways but given the nature of your interest you would need to avoid creating bias in the study overall. I'd suggest some kind of design where you have one single-sex group of males, one of females, and one mixed addressing each focal topic, backed up by a broader sample of single interviews. If you do within company studies, then you could include in your sample companies that have already been recognised for their exemplary equality policies (Judy Wajcman did this in her 1998 study Managing Like a Man, and she found that even in these companies it is not the policy that makes a difference but the culture that interprets and conditions the application of the policy).This concern with policy activation through attention to process and culture is a recurrent theme of the reports of the Equal Opportunities and Human Rights Commission in the UK (called Sex and Power, they come out every two years - one is due this year) where despite greater workforce presence by women, presence at board level still languishes below 20% for most types of organization.