to geld or not to geld

[Linny]

Alfred Vanderbilt was asked once about gelding and said (I paraphrase) "If I had gelded every colt I ever had, I'd have only made one mistake." he spoke of Native Dancer.

For all but the very best runners, you are probably better off gelding them. Some of the best runners materialize after the procedure but if they never get to show their best, they'll not likely be well supported in the stud. Also, look at how many top class racehorses fail at stud anyhow.