The saga of human evolution is also a story of two male glands, both of which produce fluid that makes up semen. One gland, the prostate, is prone to cancer. The other, the seminal vesicle, is remarkably free of it. Only mammals have prostates. By definition, only mammals have breasts, as well.
Men have seminal vesicles, too.
In other words, man, a meat-lover has the makeup of an animal that should be a vegetarian. The fact that men eat meat seem to be a mistake that nature never accounted for. Bonobos and humans have many things in common. They don't get prostate cancer. In fact, out of the 4 million years since we split off from the great primates, it's only in the last 600,000 years that we even cooked.