"That doesn't work" and "that's unethical" are not the same thing. We can select for anything we can measure. E.g. if we did sperm harvesting from everyone who

"That doesn't work" and "that's unethical" are not the same thing. We can select for anything we can measure. E.g. if we did sperm harvesting from everyone who scored top marks in memory tests and sterilised the rest we'd get a population that's very good at memory tests (and probably also has better memory than today's average). In theory we could attempt to measure general intelligence using a battery of tests for everything we can think of and this would probably improve general intelligence. It would probably also give us all Tay-Sachs.