In genome wide association studies (GWAS). families based studies tend to have less power to detect genetic associations than population based studies. such as case-control studies. This can be an issue when testing if genes in a family based GWAS have a direct effect on the phenotype of interest or if the genes act indirectly through a secondary phenotype. https://www.vacuumdoctores.shop/product-category/obsolete-parts-with-alternative-or-secondhand-available/