**Core Concept**
Orchidopexy, also known as orchiopexy, is a surgical procedure to correct undescended testes in males. The goal is to bring the testes into the scrotum and improve fertility and testicular function. The timing of orchidopexy is crucial to prevent testicular damage and promote optimal development.

**Why the Correct Answer is Right**
The American Academy of Pediatrics recommends that orchidopexy be performed by 18 months of age to prevent testicular atrophy and improve fertility outcomes. This timing allows the testes to undergo normal development and reduces the risk of testicular cancer. The procedure is usually performed after 6 months of age, when the testes have fully descended into the inguinal canal. Early intervention is essential to prevent complications such as testicular torsion and infertility.

**Why Each Wrong Option is Incorrect**
**Option A:** Performing orchidopexy at birth may not be necessary, as some testes may descend spontaneously. However, early intervention is still recommended to prevent testicular damage.
**Option B:** Waiting until puberty to perform orchidopexy is too late, as testicular atrophy and infertility may have already occurred.
**Option C:** There is no consensus on waiting until a certain age, such as 3 years, to perform orchidopexy, as this may lead to testicular damage and infertility.

**Clinical Pearl / High-Yield Fact**
The "6-18" rule is a useful mnemonic to remember the timing of orchidopexy: perform the procedure between 6 months and 18 months of age to prevent testicular damage and promote optimal development.

**Correct Answer: B. Waiting until puberty to perform orchidopexy is too late, as testicular atrophy and infertility may have already occurred.**