1. President Obama and Mrs. Obama are looking to have another child. They are both heterozygous for rolling their tongues, which is a dominant trait (R). What are the possible genotypes for their next child? Phenotypes? To solve this problem follow the steps below Step 1: Write out the parent genotypes cross: Step 2: Punnett square: Figure out the gametes. Put the parent gametes in the proper locations & fill in the boxes.