I just read recently that stretch marks aren't actually from stretching, they're from damage done by inflammation (from various causes).
That bit of trivia isn't really helpful, but kind of interesting.
Most of my stretchmarks occurred during puberty and adolescence, and they've faded about as much as they're going to. I started looking at them differently though after a stand-up comedian compared his gf's stretch marks to tiger stripes, and how beautiful and sexy he found them.
Hey, I'm willing to run with that.