Fertility is the ability to have babies or to reproduce. When fertility rates in a community increase, more babies are born.
Fertility is the quality of a human's ability to produce offspring, which is dependent on age, health, and other factors. The noun can also refer to the state of a plant or animal's being capable of reproduction. When you hear about "fertility rates," it means the number of births that happen during a certain time period in a specific location. The Latin root word is fertilis, "bearing in abundance or fruitful," from ferre, "to bear."