I think that all the discussion about why men and women seat differently popping up is great in order to get more people involved in what men/woman/human rights discussions are about.

That said, I've seen plenty of people arguing in favor of "ManSpreading" solely on the base that men have outwards lying genitals (AKA: Dick and Balls). While this is a main reason why most of us don't stick our legs to each other, it's not the only reason, nor the reason why the angle between legs is closer to 45 degrees than to, say 30.

Male and female skeletal structures are different, and even between individuals these changes mean everything for body posture. Here is an example of how pelvic bones are different.

I think this is a main reason, and I also think you can test this by telling a man to relax sitting in a bed, and in a hard chair. The extra space given by soft surfaces better accommodates our leg bones to sit at a closer angle to each other.

Even women that have thinner hips have trouble sitting with their legs tight for long periods of time, as it requires constant pull from our muscles to keep them in that position, which is something most people don't do when they are in a resting position.

I think it's important to keep people on topic that

  • Humans are a sexually dimorphic species and we need to understand our differences to achieve equity.
  • The differences we should focus are if our physical bodies are shaped different and not our minds
  • And so, seating manners are more of a balance between comfort of myself and others and not a matter of whether I can keep my junk under control or not.