After examining two large databases of traits in spouses, researchers discovered that the tendency for individuals to mate with others who possess similar traits is strongly linked to genetic correlation estimates and likely plays a significant role in these estimates.
Genetic correlation estimates typically assume that mating is random. But in the real world, partners tend to pair up because of many shared interests and social structures. As a result, some genetic correlations in previous work that have been attributed to shared biology may instead represent incorrect statistical assumptions.
Based on their analysis of two large databases of spousal traits, researchers found that cross-trait assortative mating is strongly associated with genetic correlation estimates and plausibly accounts for a “substantial” portion of genetic correlation estimates.