Everyone acknowledges that breastfeeding is the best food for your baby. God designed things are better than man designed things. There are many benefits to it: better nutrition, better health, better immunization, less allergies. If you aren't familiar with the benefits, google benefits breastfeeding.
Anyway, many Christian women have a hard time breastfeeding in public. I think this is a mistake. Younger women need to see that it is normal and natural. I also understand about modesty. I am not a topless kind of woman myself. Anyway, I found a cool video that shows how modest public breastfeeding can be. It also gives tips for breastfeeding clothing.