What is the general risk of recurrence of a birth defect in a first-degree relative?

The correct answer reflects the general risk of recurrence for many common birth defects in a first-degree relative, which is estimated to be around 6%. This statistic is based on population studies that have evaluated the recurrence of major congenital anomalies, such as neural tube defects and congenital heart defects, among family members.

Understanding the risk involves recognizing that first-degree relatives share approximately 50% of their genetic material. Therefore, if a birth defect occurs in a first-degree relative (like a sibling or a child), it suggests a potential genetic or environmental influence that may similarly affect the risk in other relatives. While specific defects may have varying recurrence risks—some being higher or lower—6% serves as a general guideline for many significant birth defects across populations.

The other options represent different percentages often misinterpreted in the context of recurrence risks. The choice of 2%, for instance, is often too low for most major birth defects in first-degree relatives, while 4% and 8% may be relevant for specific cases but do not accurately reflect the broader statistic for first-degree relations. Hence, the 6% figure best encapsulates the average risk for recurrence of various birth defects in first-degree relatives.