A male presenting with a 5-year history of infertility and low sperm count is found to have bilateral conditions increasing scrotal temperature. What is the most likely diagnosis?

The diagnosis in this scenario is most likely varicocele. A varicocele is characterized by the dilation of the veins within the scrotum, which can impede normal blood flow and lead to increased scrotal temperatures. Sperm production is particularly sensitive to temperature changes, and elevated temperatures can adversely affect spermatogenesis, potentially leading to infertility and low sperm counts.

In this case, the patient's history of infertility combined with low sperm count supports the idea that there is an underlying issue affecting the testicular environment. Varicoceles are the most common cause of male infertility that is linked to elevated scrotal temperatures.

Additionally, varicoceles typically present bilaterally rather than unilaterally, which aligns with the information provided about the patient's condition. Other conditions such as cryptorchidism, hydrocele, and testicular torsion have different presentations and implications regarding fertility and are less associated with the gradual development of infertility over time due to temperature regulation issues. Thus, the presence of bilateral conditions indicating elevated temperature in the scrotum strongly suggests a varicocele as the likely diagnosis.