Which of the following statements is true regarding first-cousin marriage?​

A) ​It roughly doubles the risk of birth defects or infant mortality.
B) ​It triples the genetic risks to unborn children.
C) ​It produces significantly healthier children.
D) It has no detectable difference in birth defects from non-cousin marriage.

First-Cousin Marriage

A marriage between individuals who have one set of grandparents in common, legally and culturally allowed in some societies but prohibited in others.

Birth Defects

Physical or biochemical abnormalities present from birth, which can cause physical or mental disabilities.

Infant Mortality

The death rate of infants under one year of age, a significant indicator of health care quality in a region.