Females of most common deer species typically have one to three fawns per year. The number of fawns depends on the species and, often, on the age of the doe.
White-tailed deer, the most common North American species, typically have one to three fawns per year per mature doe. Mule deer, common in the western United States, usually give birth to a single fawn in their first breeding year and twins thereafter. Red deer, native to Europe, northwest Africa and North America, usually produce one to three fawns per year. Roe deer of Europe have a similar reproductive pattern. Fallow deer, which can be found in Europe, Asia Minor and North America, usually produce only a single fawn per doe but can have twins.