"As far as wages are concerned the only difference between immigration and birth is that birth takes longer. When your neighbor has a child it as equivalent to a worker entering the country 18 years in the future. The wage argument against immigration thus also suggests that we should have prevented the parents of the baby-boomers from having children."Plus birth gives us workers that look like us by definition, immigration doesn't, and that bothers people. Sometimes it bothers people so much that instead of just letting people come who want to come they argue that we should choose the "best and the brightest" - whoever THAT is. And notice the people who talk like that never use the corollary. They never call the people that don't fall under their definition of "best and the brightest" the "second-best and relatively dim" or even "the worst and the dumbest".
No, they don't say that. Because that would give away the game.