Increased risk of hereditary diseases and birth defects
In marriages between close relatives, the similarity of the genetic material of the parents is much higher, which increases the likelihood of hidden (recessive) diseases. Scientific studies show that in the general population, the risk of birth defects is about 2-3%, while in marriages between relatives this figure reaches 4-6%, that is, it almost doubles.
In addition, some studies have noted that congenital anomalies occur in 2.8% of cases in children from marriages of relatives and only 0.9% of cases in children from marriages of unrelated people. From a genetic point of view, in first-degree relatives, the similarity of genes is approximately 12.5%, which significantly increases the likelihood of a combination of genes causing diseases.
As a result, children born in such marriages are more likely to have hereditary blood diseases, metabolic disorders, and abnormalities of the nervous system, which is confirmed by scientific evidence.
Disability and developmental delay
A high degree of genetic similarity affects not only specific hereditary diseases, but also the overall development process of the child. Studies show that children born in marriages between relatives are 1.5–2 times more likely to experience physical and mental developmental delays. According to some epidemiological observations, the risk of child mortality and disability in such marriages may be 3-4% higher, while in the general population this figure is estimated at 1-2%.
It is also noted that the probability of having children with hearing and visual impairments in the marriages of relatives increases by 2 times. Weakened immune systems and frequent illnesses are also more common in children from such marriages, which is confirmed by scientific observations.
Experts emphasize that this problem must be approached not only from a medical, but also from a social and educational point of view. Pre-marital medical and genetic counseling (genetic screening), raising public awareness and strengthening preventive measures help reduce the risk of negative consequences.
