YES! You won't "scar him for life". If you treat it as the normal thing it is, he will see it as normal. My son is 4 and he says, "Breasts are for feeding babies!" He'll be one man in the US who understands what breasts are really for! I think when we hide from our children (who are so understanding and adaptable) we perpetuate this idea that breasts are sexual and that nursing should be hidden. Help raise more boys with advanced awareness!!!
My son really is not affected. How would it be bad for him to see? He sees mommy nurturing his younger siblings. Granted, my son nursed untl he was 2 almost to when he sister was born, weaned himself, and then saw me nurse his sister. she nursed almost until the new baby was born and now the new baby nurses. So he has seen me nurse 2 babies besides himself at this young age. He's also seen my sister nurse her youngest. He doesn't stare, he doesn't even really notice because we have never made a big deal out of it. It's a natural part of life in our world. He's seen a few of my friends discreetly nurse, and he doesn't even take special notice, unless he says in his 4 year old way, "She's nursing her baby, mommy."
If you prefer to be discreet, sure. But don't hide. Use this as a time to teach your son what breasts are really about!!! I wish there were more books for children about this, but there aren't. Here is one that I bought for my son (and we still read it, though Daddy HATES when my son asks for it!) http://www.amazon.com/Made-Mamas-Milk-Mary-Olsen/dp/09715...
Yay! Time to raise another enlightened boy who will turn into an enlightened man who understands that breasts were made for breastfeeding babies!