Ultimately, it will probably be impossible to know exactly when or why breasts evolved. There is no fossil evidence for breasts. We don’t exhume Lucy and know her cup size.
But the debate matters. It colors how we view breasts, who they’re really for, and how we treat them. The origin discussion is worth having, and maybe someday we’ll appreciate breasts in more ways than we do now. In fuller, softer, more ponderous and pendulous ways.
—Florence Williams, author of Breasts: A Natural and Unnatural History, in an original essay on Powells.com