Consanguinity refers to a close blood connection, often associated with human inbreeding. When individuals who are closely related reproduce, it can lead to significant health issues in their children. All humans carry rare recessive genes that, when paired with similar genes, can result in genetic disorders. First cousins have a shared set of grandparents, which means there is a one in eight chance that they might inherit the same allele from the same ancestor. Consequently, marriages between first cousins, and especially among closer relatives, are typically discouraged and are illegal in many parts of the world. Unions between more distantly related individuals pose fewer risks. For families where a recessive genetic condition is known or suspected, it is recommended to undergo genetic testing and counseling, even if the degree of relatedness is minimal, such as in marriages between third or fourth cousins.