Until Earth girls catch up and develop at least a third breast, it seems unfair to even try to compare.
But does it have to be next to their butthole? Those Mars gals are kinda a buzzkill because of it... It's like looking at an inverted cow.
Reminds me of one of my favorite Point/Counterpoint articles from The Onion:
"Darling, I Will Give You The Moon And The Stars" (by an English grad student)