Consider the genetic cross for absent-mindedness, which is a dominant trait. All of the offspring from this cross will be absent-minded. If two parents that are absent-minded have offspring that are not, what MUST be the genotypes of the parents?
This is because when you cross these genetics in a punnet square, you get the possible outcomes of DD, Dd, Dd, dd. Therefore, there was a 25%chance of each offspring getting the gene, but each child did get the recessive trait.
