The AQHA recommends that you register your babies as geldings if that is what you are planning to do. It keeps them from having to mark papers later. As the colt is Brennen's, we planned on gelding him so registered him as such. We've never sent in a vet report on other horses, just informed them that we had gelded a stud and they changed his papers. Apparently, they will change him for us, but it might end up as a hassle.