Baby skin is sensitive, we all know that. But why? When your baby is born, he isn't fully developed yet. The first year of his life is spent in physical and mental development. The top layer of his skin called the dermis, like the rest of him is still undercooked, so it is susceptible to damage. His skin layer is also still very thin, so it easily absorbs anything you apply on it. That's why you should avoid applying harsh chemicals on your baby's skin.