I know when I was selecting stallions, I often ran their numbers of fillies vs. colts, looking for those who seemed to throw the "X" chromosome. I had quite a few "filly producers" here, as I always seemed to have a more difficult time selling colts, if they weren't being sold as stallion quality. But I placed many a colt as a first horse for children on gelding contracts to many 4-H'ers, and as potential driving horses. The "cost" of the horse was the gelding at my vet, which was reasonably priced, and I just wanted to move any "extra" colts anyway, so it was more important to get them in good homes.
I still laugh, as there is a 4-H horse club here, and when I first got involved, NOT ONE CHILD owned a horse!! I couldn't believe it! So, I did find a good outlet for non-stallion quality colts, and the kids loved it! They showed them in local shows and had a blast!