Have you ever heard that breast feeding can leave a woman with saggy breasts? That's a myth.
According to a big study at the University of Kentucky, they found that breast feeding has nothing to do with a loss of perkiness. But they did find some definite factors to blame for that. Namely age, but also smoking.
Apparently, there's a protein in the skin called elastin which helps support the breast, and smoking break down that protein.