I think you're stereotyping quite a bit there...
For many years, I worked full time in a department store, which here in the US meant that, outside of a couple of departments, it was a heavily female-dominated environment. I learned that women can (and are) every bit as crude, dirty, and disgusting as guys... In fact, y'all are worse!
Doing search warrants and working as a cop, I've learned that women can be at least as dirty, and messy as guys. I won't detail the things I've found... I think it suffices to say that I consider searching a female's room to be a biohazard, and I take appropriate universal precautions.
And I've found and known guys who wouldn't think of leaving a dirty sock on the floor, or failing to put something away. (In fact, in many ways, I'm neater than my wife!)
I do think that you won't find many of the roommates being romantic couples unless they already were -- but mostly because of simple familiarity, not anything about "seeing what they're really like."