Nothing really sagged except my tummy pooch after two kids. I was happiest with my body shape at around age 30. I was slim, toned and looked great. Then I had kids and things changed a bit, mostly because I simply do not have time to get to the gym or pool as much as I need to. I don't have stretchmarks but then, no one in my family does. Basically, if you take care of yourself through excercise, eating right and not too much of the hooch, your body will be fine. Yes, probably a size bigger or a slightly different shape after kids, but in some ways, even better.