A newborn Filipino girl named Danica is being championed as the world's symbolic 7 billionth baby. It's impossible to know Earth's population in real-time, but the UN estimates the 7 billionth person was born at some point on October 31. This has led to other countries claiming their own 7 billionth babies, amid pomp and circumstance. The milestone isn't all fun and games. It highlights the growing problem of overpopulation.