The ideal timing for surgical correction of undescended testes is 6 months – 1 year of age. Orchiopexy should not be performed before 6 months of age, as testes may descend spontaneously during the first few months of life. The highest quality evidence recommends orchiopexy between 6 and 12 months of age. Surgery during this time frame may optimize spermatogenic functions.
Sources:
Chan E, et al. Ideal timing of orchiopexy: a systematic review. Pediatr Surg Int. 2014 Jan;30(1):87-97. PMID: 24232174.
Kim SO, et al. Testicular catch up growth: the impact of orchiopexy age. Urology. 2011 Oct;78(4):886-9. PMID: 21762966.
Kollin C, et al. Surgical treatment of unilaterally undescended testes: testicular growth after randomization to orchiopexy at age 9 months or 3 years. J Urol. 2007 Oct;178(4 Pt 2):1589-93; discussion 1593. PMID: 17707045.