Which factor is least likely to be a cause of male infertility?

When considering factors that contribute to male infertility, it is important to analyze how lifestyle and health conditions impact reproductive capabilities. In this context, being overweight can indeed impact fertility levels by leading to hormonal imbalances, affecting sperm production and quality, but it is less directly linked to infertility compared to other factors listed.

Daily cycling classes, for instance, can lead to issues such as erectile dysfunction or lower sperm counts due to the heat generated and pressure placed on the groin area during prolonged cycling periods. Smoking cigarettes has a well-documented negative impact on sperm health due to the accumulation of toxins, which can impair sperm mobility and morphology. Similarly, certain medications, such as calcium channel blockers, can affect hormone levels or sperm production, potentially leading to fertility challenges.

While weight can influence male fertility, it is typically considered less of a direct cause than the other factors identified. Thus, overweight body mass index is the least likely to be a direct cause of male infertility in this comparison.