Children Between Cousins – Are There Risks?

Love is a beautiful, magical feeling that happens when you least expect it. It takes over your life and thoughts in an uncontrollable way, and suddenly, you’re living the beginning of a new story. One thing is very obvious and well-known: we do not choose whom we love—it just happens. And this can even occur within a family, between cousins. So what happens when this occurs? Besides family approval, the first big concern is about having children between cousins, as we’ve always heard about the risks. But do these risks really exist?

Since the beginning of time, it’s been known that marriage between first cousins is said to carry higher risks of having children born with disabilities. But this is not a guarantee—it’s simply a slightly increased percentage compared to average, something that can also happen in couples without any blood relation. Genetic problems can happen to any couple!

Any couple, even those not related, have a 3% chance of having children with genetic problems¹. This risk increases to 6% in couples of the same bloodline and up to 7–8% in couples who share the same defective genetic codes, which is quite common among first cousins. For cousin couples who already have a family history of recessive diseases or who already have a child with a genetic disorder, the risk rises to 25%.

To clarify: if a woman carries an altered gene that causes deafness and the man carries a different mutated gene that causes blindness, the baby will not be at risk of being born either deaf or blind. But if both parents carry the altered gene causing deafness, there is a high chance the baby will be born with hearing problems². Genetic problems occur due to the combination of the same altered genes from both parents, which is why the risk increases for children of cousins, especially if there are already cases in the family. The most common problems seen in children between cousins with the same genetic codes are: Cystic Fibrosis, Mucopolysaccharidosis, Sickle Cell Anemia, Albinism, and Metabolic Diseases. These conditions range from growth and childhood physical and motor development issues to even intellectual delays. It all depends on the type of altered genes the parents have, which can trigger different kinds of diseases³.

I Married My Cousin and Want to Have Children – What Should I Do?

The decision to have children must be made by the couple, and all possibilities and risks should be discussed. If the decision is still yes, certain precautions should be taken. The first and most essential step is to seek out a genetics specialist, who will perform tests on the couple to analyze possible genetic alterations and provide thorough genetic counseling. A pedigree will be created to assess the family history of any recessive diseases.

After this pedigree analysis, if altered genes are found and risks identified, the decision to go ahead and have children must be made by the couple. It’s important to note that in Brazil, abortion is not allowed if a genetic disease is detected during pregnancy, so this is a very serious decision that must be made together. Good counseling and medical follow-up are essential for understanding the risks and chances before making your decision! Children are for life—always keep that in mind!

See also: Do You Know Sign Language for Babies?

Photo: Rodrigo Moraes