I am teaching a basic mathematics class, and am using Punnett squares as an example. In order to keep the students' interest, I am looking for examples of human traits, no Mendel's peas and so forth are not what I need. I wish to keep to monohybrids, as dihybrid hyprids would be too confusing for these students. I used widow's peak/ straight hair, but other examples I look at turn out not to be really the case: for example, eye color is determined by more than two genes, hair color can mix, lateral tongue rolling and attached ear lobes turn out also not to be as straightforward as the common myths have it, and so forth. Can someone give me some nicer, and valid, examples? Thanks.