I tried it once but insteed of hearing "male or female" it just said straight, or gay"
honestly I dont think theres any "big psycological" thing into it and its just gendernorms.
like said, many would think it to seam more girly to look at your fingers like that, but I also thought of another thing.
nail polish, if you having this most people tend to streight out there fingers to look at the result. and in general I feel if I dont care of my nails I look at them the typical way with the front facing me, but if im doing something" with my nails, to make them look "pretty, or just a certain way, like if im to dress up as something and using nail polish for my look, then I look at them the other way. also I notice other guys doing that, when they dont care about there nails they just look at them but if they had done something with them like manicure*(not sure how this is spelled) then they tend to look the other way.
I would say nailpolish, manicure, and general all this about taking care of your nails is seams abit femenine, so obviously its the "girly" one, which guys dont want to do as many guys are scaared of being seen as girly or femenine.
So no big surprize for me.