Yup. Why? Because sex for humans is about more than just procreation. You go anywhere in the world or to any point in human history and you will find examples of homosexuality. It is natural in the sense that is is part of the human condition. That does not mean it is moral. Things like murder and rape are also part of the human condition.If your life depended on the answer being correct as far as which is natural and which is unnatural, you'd go with penis+penis=natural? Is that your final answer?