Let's put it this way.
What if male Shepard's special outfit for Kasumi's mission involved a kilt that was a little short. An argument would be when Shepard(male or female) sits in front of Garrus, no one wants to see where the sun don't shine, and Shepard(male or female) should close their legs.
However the argument I keep seeing when it comes to femShep is because she is a woman and women don't sit like that. That's what is annoying me about this argument about making female Shepard have so called "feminine" animations. It's not about what's natural, it's about what a woman's behavior should be.
To me "feminine" walk and "feminine" sitting is through social influences. For a woman to get her hips to truly sway, they need to learn to walk on a line. That is what fashion models do on the run way. Men actually have a sway in their walk too if you watch carefully, it's just how humans walk. I think the illusion of a natural sway created by women is through the curve of the hips. Which is what we see in cut scenes when femShep is walking and it appears as though her hips sway. She's still using the same exact walk as male Shepard, she just has hips that creates the illusion of a sway.
I've had a friend who's mother constantly berated her for how she walked because it wasn't "feminine." Honestly now that I think of it, she walked like femShep. Very so called "masculine." She wasn't even an athlete or soldier. In fact she was pretty so called "feminine" in personality, liked pink and make up. But her walk wasn't so called "feminine." To me, it's something social.
If a woman is wearing pants, then she should sit how she feels comfortable, which could mean with her legs apart. I don't understand where it goes from being inappropriate when sitting in a chair, to appropriate when a woman sits cross legged or in a meditation type position. Is it because her feet are in the way now? If she were wearing a dress she'd be exposing herself far worse. My only conclusion is there some kind of social silliness behind it.