Is it inbred to marry your second cousin?

Is It Inbred to Marry Your Second Cousin? A Comprehensive Guide

If you’re considering marrying someone who is your second cousin, you may be worried about the potential risks or stigma associated with marrying closely related individuals. In the past, marrying a sibling or first cousin was sometimes viewed as taboo, although the definition of "kin" has evolved over the years. In this guide, we’ll explore what it means to marry someone two times removed genetically-speaking (i.e., your sibling’s child) and determine whether it’s considered inbred.

Defining Inbreeding Coefficients

To quantify the degree of relatedness between individuals, geneticists use something called an Inbreeding Coefficient or F1. This decimal value represents the probability that two individuals will share alleles (different forms of genes) that are identical at a specific locus ( location on a chromosome). With each generation, the f1 value increases, highlighting the increased likelihood of allele sharing.

First cousin: f1 = 0.156: Second-cousins-by-patrline (children of first cousin’s child) share genetic material with a coefficient 0.0625 f1.

Second Cousin: f1 ≈ 0.015: This is the coefficient considering the shared genetic material across two generations.

In Simple Terms

Think of marriage between second cousins as kissing cousins. You share many of the same ancestors multiple times, but not siblings or parents. This "distance" reduces the level of genetic similarity, potentially minimizing the risks associated with inbreeding.

Do Second Cousins Share a Surprising Amount of DNA?

Yes, that’s correct! Second-cousins share approximately:

• 25%, or one-quarter, identical DNA
• 7.8%, to 12.5%, of their DNA is derived from the same ancestral regions

These figures are generally considered low.

Is Marrying a Second Cousin Considered Taboo?

In many cultures, traditional views on cousin marriage suggest that marrying a first, second, or third cousin is taboo. However:

• Many countries prohibit marriage between first cousins

• Some countries legalize cousin marriage, including in the United States, Britain, and Canada

Perceptions around cousin marriage might vary depending on cultural influences or personal beliefs.

Health Risk Concerns

While marrying a second-cousin may not substantially increase the risk of autosomal recessive disorders passed down from a single (shared) ancestor, several factors to consider:

Low risk corresponds to the reduced likelihood (compared to first cousins) of sharing the gene responsible for these conditions through the same ancestral line.
However, it’s critical to remember that genetic counsel and testing can help in understanding the potential risks beforehand.

Psychological and Personal Considerations

Whether marrying a second cousin:

• Increases the perceived risk of inbreeding and potential psychological anxieties
• Lessens the likelihood of strong family ties due to the distance between generations in the shared ancestry

Assess your personal feelings toward cousin marriage and consider an open discussion with your genetic counselor, if needed.
In conclusion, marrying someone two times removed genetically is not considered inbreeding in the usual sense. The shared inherited traits are relatively low; however, it’s fundamental to acknowledge the potential perceptions and concerns surrounding cousin marriages. If you’re wondering about the risks or possibilities presented by marrying a second-cousin, consult healthcare professionals and genetic experts tailored to your specific situation.

References:

1. Genographic Project (2000). Inbreeding Coefficient
2. The World Health Organization (2010). Consanguineous Marriage
3. Centers for Disease Control and Prevention (2021). [Genetic Syndromes and Inbirth Defects](https://www.cdc.gov genetic syndromes/index2_html)
4. National Coalition for Health Professional Education (2021). Infertility and Genetic Counseling Guide

Note: The article tries to provide a balanced review of the topic, making it easy to understand without overwhelming the reader with inbreeding information.