Gender Segregation in Small Groups and Prayer

TL;DR >What Biblical justification is there for gender segregation in prayer/small groups? and has there been any study on the affect which this segregation has on the people involved? --- In various churches, I often come across gender segregation in one form or another. This is even in _fairly_ progressive churches, eg ones in university areas with large student populations. (I'm talking about the UK here. I know that _progressive_ needs to be taken differently depending on the location. In particular, there is a significant difference between UK and US approaches to church-life.) Perhaps the most common one of these, and the one I would like to address in this question, is to do with small groups and prayer. At one local church (the largest in the town, which is really a "university-town"), all the student small groups are completely gender segregated. In another, the small groups are mixed gender, but at the end they separate off, male and female praying separately. I have heard the argument that "sometimes women want to speak about certain things only with another woman". I am not a woman (in any sense), so I cannot speak personally about this. However, it seems unreasonable to make that argument regarding praying in a group of up to 10 people, many of whom you may not know well. Asking to pray individually with a (fellow) woman is a _completely_ different matter. So my question boils down to the following. >What Biblical justification is there for such gender segregation? Gender segregation gets a bad rap outside of churches for well-documented reasons. Further, there has been significant studies on the effects that it has on people. Searching, I was unable to find material specific to the situation I describe -- understandably; it's fairly niche.