Thoroughbreds cannot be registered as such on the register kept by the Jockey Club if they are not conceived naturally in front of witnesses. Artificial insemination and embryo transfer permitted for other breeds are prohibited in Thoroughbreds. If such prohibition avoids any error in the attribution of parentage, it also makes it possible to maintain the coverings of the stallions of the most popular lines at very high prices by limiting each stallion to reproduction with a few hundred mares per year. In France, the coverings of stallions like Anabaa, Sinndar, or Green Tune are invoiced between 15,000 and 27,000 euros, but the price of certain coverings can reach more than 100,000 euros.