they're not kidding

Among other things, I study the history and philosophy of eugenics in the US and UK from 1899 to World War 2. A person I met the other day told me this was a stupid thing to study. "Eugenics," he said (I'm paraphrasing), "was the upper classes trying to toy with biology without knowing about genes. Since we know about genes, we know we can't make a perfect human society." He had a good point. But it was a good point if we were living in 1940. Obviously, we no longer have people calling for the sterilization of the "feebleminded" or the "conspicuously disorderly." We do, however, have more than a few people who believe--much like their American, British, and German counterparts in the last century believed--that for the good of future generations, we must reduce the population of our planet. This is all well and good, of course, unless you're of the people groups that tend to "overbreed" and are, therefore, undesirable. No doubt there are parts of the world where the population really is outstripping the ability of the land to provide food. But does it follow: (1) that keeping people from breeding is the best way to "save the planet" or (2) that forced eugenic practices are preferable to what might happen if nothing is done?