A male horse, a stallion, is often referred to as the sire, while the female horse, that is producing the offspring, is called the dam. Both are genetically important; each parent contributes half of the genetic material of their offspring, which is called a foal. A foal is a baby horse up to one year of age. Male foals are called colts and female foals are called fillies. When a mare or a dam has delivered a baby horse, we say she has foaled. Once foals turn one year old, they are normally referred to as yearlings.