What is the primary reason for genetic recessive disorders occurring among the Amish community?

Genetic recessive disorders are more prevalent in the Amish community primarily due to limited inter-community marriages, a factor that leads to a higher degree of genetic homogeneity. When a community practices endogamy—marriage within a specific group—the gene pool becomes restricted. This is particularly relevant for genetic recessive disorders, which require two copies of the recessive allele for the disorder to manifest. In a genetically homogenous population, there is a higher chance that individuals will inherit the same recessive alleles from both parents, leading to a higher incidence of these disorders.

In contrast, the other options would not have the same significant effect on the prevalence of genetic disorders. Environmental toxins may impact overall health but do not directly influence the inheritance patterns of genetic conditions. High rates of immigration could introduce genetic diversity, potentially reducing the incidence of recessive disorders rather than increasing it. The use of advanced medical technology primarily addresses diagnosis and treatment rather than altering the underlying genetics of a community.