Alsohuman
I completely disagree
A male flaccid penis and testicles in our culture are not the equivalent of a woman with her legs apart at all.
Yours is the false equivalency.
Maybe a man laid back with an erection
How would you feel about an artist painting a picture of his 17/18 year old son laid back with his legs spread and a hard on?
This pretence that in our culture there is nothing sexual about a naked woman with her legs spread is ridiculous.
And the drawing comparison with nowhere equivalent images of men/ Michealangeo's David 
There are so many double standards here
In our press it used to be the case that on front page mens nipples were fine, womens had to be covered
Open leg women in porn mags were fine but erect penises not
This is all related to ideas about men, women, sexuality, and a whole host of stuff that has been analysed in far more detail than there is time for here!