Cleft lip and palate etiology and its meaning in early 20th century England: Galton/Pearson vs. Bateson; polygenically poor protoplasm vs. Mendelism.

At the outset of the 20th century in England there arose a venomous dispute between Mendelian geneticists such as Bateson and anti-Mendelian biometricians such as Pearson over the genetic etiology of such "physical deformities" as cleft lip and palate. To Pearson et al., such traits were an expression of physical and racial degeneracy which could be traced to polygenically poor protoplasm. To Bateson et al., such traits were Mendelian unit characters whose segregation could be seen in carefully constructed family pedigrees. Bateson dismissed the work of the anti-Mendelians as "unsound in construction" and predicted such thinking would inevitably lead to "brutal" control of those the larger society deemed unfit. History proved Bateson astutely prescient.