In Japan, the concept of family extends far beyond the nuclear unit, and cousin marriages were once a common practice in rural areas. Family honor and preserving the bloodline were seen as paramount, leading to the idea of intermarriage between cousins. However, with modernization and increased urbanization, this practice has declined, and it is now much more uncommon.
Marriage between cousins was once a common practice in Japan, but has since decreased sharply since the 1960s. Japanese cousin marriage in some areas of Japan can be as high as 5%, but nationally it is approximately 1% of the population. variety of factors have contributed to this shift, including the declining size of families, increased access to modern transportation, the migration of young demographics to urban areas, and an increased awareness of the potential genetic risks associated with consanguineous marriage. Despite these changes, cousin marriage is still legally permitted in Japan.
Cousin Marriage in Japan – Meiji to Now
Japan has a rich history of cousins marrying cousins, shaped by a variety of geographic, cultural, historical, and economic factors. In the past, isolated communities with limited access to outside populations relied on cousin marriage to maintain their unique gene pools and cultural heritage. Marrying within the family also served to keep wealth and property within the family, and to prevent young people from leaving their homes and communities.
Prior to the Meiji Restoration, Japan was a highly stratified society, and people were generally forbidden from marrying outside of their social class. This led to a greater prevalence of cousin marriage, as people were often limited in their choice of potential partners.
Religion also played a role in the practice of cousin marriage in Japan, as different religious communities tended to keep to themselves and marry within their own families.
Despite these historical factors, the practice of cousin marriage has declined in recent decades due to a number of social, economic, and educational changes. Nevertheless, the legacy of consanguinity in Japan continues to influence the nation’s cultural and genetic landscape to this day.
Health Implications for Cousins Marrying in Japan
Nowadays, it’s common knowledge that marrying close family members like cousins comes with a higher risk of congenital disabilities in children born from these marriages. This is why it is discouraged and sometimes illegal in many countries. First cousins have 12.5% of their DNA in common. A child born from a consanguineous marriage will share a good proportion of similar genes. Where parents are not related, and one parent provides a defective gene, the chances are that this will not affect the child if the other parent has a completely different set of genes. The children of first cousins have a 4-7% risk of congenital disabilities, while those born from parents with dissimilar genes only have a 3-4% risk. It is not a huge difference in risk, but the problem would escalate once those children began to marry their first cousins. They would share more DNA and have a greater chance of bearing children with congenital disabilities. Common Birth Defects Resulting From Cousin Marriage When a married couple shares a common ancestor, the chances of having the same gene abnormalities are increased. The risk of defects and genetic diseases include:
- Cleft lip and palate
- Extra fingers and toes (polydactyly)
- Spina Bifida
- Congenital heart disease
- Certain hereditary cancers can develop later in life
- Some psychiatric conditions can be inherited.
Marrying Cousins More Common Than Thought
Despite the known risks, there have been several notable individuals who have married their cousins, including:
- Al Pacino
- Queen Isabella of Spain
- Vincent van Gogh
- Pablo Picasso
- Agatha Christie
- Albert Einstein
- Rudy Guiliani
- Queen Elizabeth and Prince Phillip
- Thomas Jefferson
- Henry VIII & Catherine Queen
- Victoria and Prince Albert Edgar
- Allan Poe
- H.G. Wells
- Charles Darwin
- Jesse James
- Jerry Lee Lewis
- Marie Antoinette and Louis XVI
- Kevin Bacon
Japan’s Direction Towards Modernity
Despite the shift away from cousin marriages, many families in Japan still place great importance on preserving family traditions and maintaining close relationships. This sense of community and obligation to family can make the decision to marry a cousin more complicated, as it involves not only personal feelings, but also the opinions and expectations of the wider family network.
It’s worth noting that attitudes towards cousin marriages vary greatly depending on individual families, and there is no one-size-fits-all answer to whether or not it’s considered normal in Japan. Ultimately, the decision to marry a cousin is a deeply personal one, influenced by cultural background, personal beliefs, and the dynamics of individual families.