The story goes that mating with a close relative passes on bad genes that lead to deadly genetic mutations. But Queen Victoria, Charles Darwin, and Albert Einstein all married their first cousins so how can it be that bad you might ask.
Well the more DNA you share, the greater the chance your offspring will have one or more of the many recessive diseases out there. Most people are carriers of millions of genetic diseases and when two carriers get a child then there is a great risk that the child will get the disease/s.
Recessive diseases are those that develop when both parents are carriers of the same condition and they both pass on their mutations to their child. (e.g Cystic Fibrosis, infertility, sickle cell disease, thalassemia, Tay-Sachs, Fanconi Anemia, Huntington's Disease, Tuberous Sclerosis, Congenital Fructose Intolerance, Down Syndrome, Albinism e.t.c)
Genes come in pairs, one from each parent. A carrier of a recessive disease is an individual who has a mutation in one copy of a particular gene that causes the gene not to function properly. Since carriers have a second working copy of the gene, they generally do not develop any symptoms of the disease, but they can pass on the gene with a mutation to their children.
Scientific evidence points out the risk to inheriting a genetic disease between cousins who have a kid is 4-7% and for the general population 3-4%.
Marrying out of your family introduces new, potentially helpful genes into the family gene pool, while marrying within your family recycles the old and possibly dangerous ones.
However, everyone considering having children should be screened.
While many diseases are more commonly found in specific ethnic groups, there is still a chance that an individual from a different background might be a carrier, as well.
At least one member of every couple should be screened. If his or her results are positive, the other member of the couple should then be screened too.
Carrier screening enables individuals, who intend on getting married and have children together, find out if they have genetic mutations. This reduces the risk of getting children, with the said conditions, by helping them plan accordingly.
Based on the results, individuals can decide not to get married, or not to have children. If they decide to get married and have children, Bioinformatics Institute Of Kenya, empowers them with information, on how to take care of children with genetic defects.
Whether hereditary diseases run in your family or not, carrier screening can provide, important information for family planning.