Adam and Eve are painted with belly buttons because the artists use other humans for references. These references have belly buttons. Painting them without the belly buttons looks strange to most people, the way aliens without belly buttons in art look strange. read more
Where the artists that painted Adam & Eve educated in theology and history to be considered experts in evolution and historical matters about the begining of humanity. I would definitetly say no. Therfore I would say that the artists most likely used models and since the models had belly buttons so they paintings. read more
Because your belly-button (navel), or tummy-button as it's sometimes called, is a sign that you were once attached to your mother. You depended on that life-line — the umbilical cord — for your nourishment from her body as you developed inside her. God would not have planted on them a false indication that they had developed in a mother's womb. read more
In the Bible, there is no detailed description of Adam and Eve, so that they had belly buttons is not holy writ as it were. Artistically, most of the paintings that we know were just as interested in displaying the human form as we know it, as any theological or historical points. And the human form as we know it has belly buttons. read more