This is nonsense. We need to look at evolution to develope a model of moral behavior. Since we are essentially self reproducing machines, all moral behavior should be directed toward the perpetuation of Life (the process, not the individual).
For Homo Sapiens this is a particularly complex problem because, in order to propagate our own specie, we must at a minimum preserve those upon which we depend. Additionally, since we are capable of destroying life on earth (and we are very close), we must assume the stewardship of Life on the planet. Otherwise, we have no idea how the chain of events will play out.
There is also the issue of what motivates each of us to continue living. This is a question that can be asked of every form of life and, I think, binds us to every other living creature. I suppose you could say it's sex but that seems a little simplistic to me. If sex is the only thing that we live for then how are our offspring to survive? After all, they, too, need to survive to reproductive age. It seems to me that experience (I like the term Zen)is the key. What we lust for, love, fear and hate are the things that keep us going long enough to preserve the well being of the next generation.
This is a new paradigm (at the risk of being immodest) for morality because what is "Good" is determined by circumstances. In the time of the Jews and Classical civilizations the simple survival of the individual was necessary to garauntee the survival of humanity. With the advent of effective medical science, everything has been turned on its head. Now, too many individuals survive for too long while the birth rate remains the same and too many babies survive to adulthood and reproduce too many more babies. In this manner, Humanity demands too much of the earth's physical capacity and will finally surpass its capacity to sustain us (and maybe Life itself)
So what is moral now? In a word, I think you may say MODERATION! More than two children per couple is immoral. Living beyond the age of independence is immoral. Promoting the idea of eternal life is immoral; we must live our lives in a way that assures the continuation of Life on the planet not our own survival. In short, in our time, if Granny Smith can't make it on her own, she's detracting from the well being of the children and she needs to go. At a later time the idea of "Good" will change again, but rest assured it will never be static.