Aliens

Here's a thought. (It's one of those wide awake at 4am thoughts, when one's mind just rambles around aimlessly).
   When you see depictions of aliens, how come they never have genitalia? Or breasts? This must signify that 1) they reproduce asexually (or have hidden genitalia) 2) they are not mammals (or have hidden breasts). They don't seem to be sexually dimorphic, but there are big ones and small ones. From this, some observers have drawn the conclusion that the big ones are male and the small ones female. But isn't this anthropocentric? Perhaps the big ones are female and the small ones male.

Second 4am thought. If you could go back in time and bring something back, wouldn't it be fun to kidnap a medieval peasant and bring him/her back and show him/her round your house? It's full of magical stuff - electricity for starters. It's an invisible energy source that is carried to the house in small wires. It's not hot, but can heat your home and cook your food. It can kill you, but mostly it's taken for granted. And microwaves - sheer sorcery. The food cooks but the cooker doesn't get hot?  That is truly a weirding way. And cars (a wagon without a horse). And phones (talking to people through a wire). To say nothing of smart phones and cell-phones (talking to people through the air). The peasant would probably have a breakdown just trying to take it all in.

So let's put these two thoughts together. Perhaps "aliens" are just humans from a far future time, come back to amuse themselves by mystifying us early-21st century peasants with their advanced technology and genderless sexuality?