A new birth control method for men known as RISUG for Reversible Inhibition of Sperm Under Guidance is under testing. The procedure involves injection of a nontoxic polymer inside of the vas deferens. The polymer forms a coating on the inner lining of vas deferens. As sperms pass through, they are chemically disabled by the polymer. Hence, there is ejaculation but the sperms are incapable of fertilising the egg. At any stage if needed, the polymer film can be dissolved and removed using specific injections.
In one of the trials that was being conducted to check the effectiveness of the method, one of the conditions was for males to have had two children in the past. What could be the reason for having such a condition?

Options

A. to ensure that they could not produce more children in future
B. to ensure that the procedure didn't have any side effects on their children
C. to ensure that the males were fertile and their partners had conceived in the past
D. to ensure that they were educated enough to understand how the method worked

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question revolves around a new birth control method for men called RISUG, which involves the injection of a non-toxic polymer into the vas deferens to disable sperm chemically.

2. **Identifying the Condition**: The trial requires males to have had two children in the past. This condition is significant for several reasons.

3. **Reason for the Condition**:
- **Fertility Confirmation**: By selecting males who have already fathered two children, the researchers can confirm that these men are fertile. This means that their sperm are capable of fertilizing an egg, which is essential for establishing a baseline of fertility before testing the effectiveness of the RISUG method.
- **Safety and Efficacy**: The trial aims to ensure that the method is safe and effective for men who have already demonstrated reproductive capability. If the method is successful in these men, it can provide a reliable option for those who do not wish to have more children.
- **Psychological Factors**: Men who have already had children may be more psychologically prepared to undergo a reversible birth control method, as they have experience with fatherhood and may be more confident in their decision to prevent further pregnancies.

4. **Conclusion**: Thus, the condition of having two children ensures that the participants are fertile, which is crucial for evaluating the effectiveness of the RISUG method in disabling sperm without affecting overall reproductive health.

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