In all my exploits with women, I've never come across any natural stretch marks (including a few formerly pregnant women) that were boner-killers.  Having said that I have my limits. But in the majority of cases the stretch marks are barely visible to me even after the woman specifically points them out. I often felt it was a thing only women cared about.  I never encounter man locker room talk about women's stretch marks unless it's a legendary circumstance.