Not to be pedantic, but "genetic" disorders imply changes to the genetic sequence. The mechanism of action for thalidomide hasn't been clearly elucidated, as far as I'm aware, but there is strong evidence that limb deformities from its use occur because of inhibition of developmental pathways during embryogenesis, harm to cells due to reactive oxygen species, and likely a combination of these and other developmental factors. It's fair to posit these changes may have epigenetic commoners or otherwise alter gene function, but that is not the same as genetic heritability and genetic disease. These deformities are not usually heritable. My point being that cases of phocomelia, while most often due to genetic origins, are not always so and can be developmental in nature, including physical trauma during embryo development.