Evolution and Micturition.

Evolution theory provides a simple explanation for any weird phylogenetic phenomenon we may encounter.

Atavistic remnants - such as the appendix, the coccyx, the supratrochlear spur or Donald Trump - can be readily understood in the context of phylogenesis (although the last example probably not so much).

One human anatomical feature which formerly seemed inexplicable is eminently logical in the context of natural selection.
The penile urethra is a handy little (or not-so-little  in the case of the Clibrig family, I am proud to say) passage which connects the male bladder with the public toilet. 
I accept that it has other functions which are familiar to the entire post-pubertal population, but these are beyond the scope of this discussion.

Probably the most interesting feature of the male penile urethra is that it is horizontally flattened in relation to the long axis of the penis (stick with me, readers, this is the whole point, so to speak,  of this discussion), whereas everybody, with the exception of the Mother Superior at St Carthage's Convent, knows that the meatus - the opening of the urethra on the glans penis - is a vertical slit.

This arrangement results in a spiral stream of urine which delays the separation of the stream into discrete droplets. (Master-class micturators would know that this occurs in a clockwise rotation.)

Which begs the question. Why? 
Why would evolution care if the male urine stream resembled the shower setting on an adjustable garden hose nozzle?

Well, like everything else in life, it ultimately comes down to sex. 
What chance would you think the average prehistoric male had of cracking a bit of nooky if his trouser legs always stank of urine?

How could a bathroom floor awash with splattered wee be in any way be regarded as a subliminal scene-setter signal for the average Neanderthal housewife that it was time for a bit of spontaneous hide-the-sausage? 

The prehistoric sprayers and scatter-gunners would have bugger-all chance of perpetuating that gene, and the urinary sharp-shooters and dead-eye dicks (so to speak) would get all the action.

So we males may be loud and whiskery and inconsiderate, and might nearly always forget your birthday, but, by god, we can piss through the eye of a needle. 

Or a barbed wire fence.