It's odd that the paper goes to great lengths to talk about protecting your penis from insects but at the same point seems to ignore women completely - all the illustrations depict men. Having met women (shocking, I know), bust size can be a significant factor in ergonomics so it would be interesting to see how that factors into it. Also anecdotally, pregnant belly-sleepers frequently rely on cushioning and people may prefer certain sleeping positions after having given birth or suffering from certain ailments. I'm also certain that waist size (esp. obesity) may alter preferences.
It's an interesting paper but given the lack of substance this feels more like a school presentation than something you'd find in an academic journal.