Why are mixed-race babies smart and beautiful?

Hybrid children are not necessarily beautiful, but also depends on their parents' own conditions and race. Generally speaking, they will have a relative advantage in physical quality, and it is just the opposite statement that marrying close relatives of the family is more likely to cause diseases. As for IQ, the advantage of mixed-race children has little to do with their own genes, but more is the advantage highlighted by parents' different cultural environment and rich language environment to stimulate brain development.