Here is how surrogate works. There are two kinds of surrogacy. Gestational surrogacy, which often uses IVF, entails the egg from the intended mother (or egg donor) being fertilized by the intended father’s sperm (or sperm donor). This embryo is then placed into the uterus of the surrogate mother, who carried the baby until birth. Traditional surrogacy is when the surrogate mother gets artificically inseminated by the father’s sperm, who, once impregnated, carries the baby until birth.