I do not think that is the original completely. During the war the germans used it for target practice. It was later restored.
Also, many womans breasts would fall in nude pictures but they seem to defeat gravity. This is called ‘artistic’
That’s a real good question. I suppose it might have to do with the fact that DaVinci, as an Italian Christian working on a commission for an Italian Christian monastery, just didn’t think to hire a Jewish technical consultant for his painting.
Michelangelo could have used one too, BTW when he sculpted David. Ever notice that HE’S not circumcised?