Basic and Clinical Sciences (BCSE) 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer revolves around the impact of smoking on reproductive health in men, specifically the increased thickness of the zona pellucida, which is the thick transparent outer layer surrounding an ovum (egg). Although it seems counterintuitive to associate smoking with a thicker zona pellucida, research indicates that smoking can alter various physiological parameters, which may inadvertently lead to changes such as this.

Smoking is primarily known to adversely affect male fertility through mechanisms like reduced sperm quality, lower sperm counts, and compromised motility. However, the notion that it would enhance or lead to beneficial changes in reproductive systems, such as improved motility or increased fertility, is not supported by evidence. Instead, smoking is linked to numerous negative outcomes in reproductive health, including altered hormonal balance, which may contribute to thicker structures surrounding the egg.

Although the other choices imply favorable reproductive effects or changes that smoking would not typically induce, they don't align with established research on the negative implications of smoking on overall reproductive health in men.