“The midwife said one of my baby’s testicles isn’t in the right place — is that serious? Will he be okay?”

UNDESCENDED TESTIS (CRYPTORCHIDISM) presents when a testis is not palpable in the scrotum — found at the newborn/6–8-week checks or noticed by a parent — and the first task is to EXAMINE properly, face to face, in a warm room with warm hands and a relaxed, warm child (cold or anxiety triggers the cremasteric reflex and can mimic an undescended testis), establishing whether the testis is in the scrotum, PALPABLE in the inguinal canal (and gently manipulable), or truly IMPALPABLE, examining both sides and the genitalia. The key distinction is between a RETRACTILE testis — which can be brought to the bottom of the scrotum without tension and STAYS there at least briefly, is usually benign, needs no surgery and is reviewed yearly until puberty because some later ascend — and a TRUE UNDESCENDED testis, which cannot be brought into/kept in the scrotum; this avoids both over-referral and missing a genuine UDT. The must-not-misses are BILATERAL undescended testes at the newborn check (senior paediatric review within 24 hours, NIPE) and ANY undescended testis with hypospadias, micropenis, bifid scrotum or atypical genitalia, which may indicate a disorder of sex development or endocrine cause (e.g. congenital adrenal hyperplasia) and needs SAME-DAY paediatric assessment; acute groin or abdominal pain with an undescended testis is possible torsion needing immediate emergency surgical assessment (GIRFT/BAUS pathway). On the pathway and timing (NHS NIPE): a testis still undescended at the 6–8-week check, or found later, is referred NOW to paediatric surgery or urology, with no ultrasound first (it does not reliably locate the testis or change the need for surgical assessment), for ORCHIDOPEXY (surgical placement/fixation in the scrotum) ideally at 6–12 months and by 18 months at the latest (EAU/ESPU 2026, international) — timing matters because earlier surgery improves fertility outcomes, and spontaneous descent after about 6 months (corrected age) is uncommon — and an acquired/ascending testis (previously descended, now undescended) also needs surgical referral. Counsel parents honestly but proportionately that a persistently undescended testis is associated with impaired FERTILITY and an increased, harder-to-detect risk of TESTICULAR CANCER, which is why timely orchidopexy (reducing but not removing the cancer risk; Pettersson, NEJM 2007) and, from puberty, testicular SELF-AWARENESS are advised — framing this as the reason for treatment, not alarm. Reassure proportionately (it is common, often resolves or is correctable, with a good outlook after timely treatment), explain the plan, support the anxious parent, and safety-net.