We are human beings, and other people are too. We should welcome anyone willing to work hard, earn and contribute. It has been proven, btw, that immigrants add more value to local economy, love patriotism, support vets, pay taxes, and are not as likely to commit crime. My spouse, and my mother, are both immigrants, both add tremendous benefit to USA.
Also,telling people they do not have the right to have children is social darwinism, and it has never worked well for anyone.