When I bought my horse he was a colt and was over a year old with only one desended testie. So naturally I freaked out and read up about crypts. As far as I gathered from various sites and vet books, a crypt cannot breed unless one testicle is dropped. If the testicle is inside the body teperature kills the sperm, also horomone levels increase and crypts are usually worse mannered then studs. If your guy is a crypt its possibe to get the other testical easily if its at least semi dropped. When a colt drops a ring closes inside them so that the testies cannot go back into the body. If its on the other side of the ring he will have to have major surgery to remove it. Like someone else said, cancer is high risk as well as some other health issues if its left. It couldnt hurt to have the mares looked at just in case though, miracles happen. Even the unwanted ones ha ha. Best of luck!
Tomorrows another day, and Im thirsty anyways, so bring on the rain.