Therefore, if the testicular artery is ligated, e.g., during a Fowler-Stevens orchiopexy for a high undescended testis, the testis will usually survive on these other blood supplies.
From the en.wikipedia.org
A current hypothesis is that perturbations in testes development may be caused by exposure to chemicals, leading to undescended testis and endocrine disorders, Skakkebaek said in an interview.