Mutations of SLC26A4 cause Pendred syndrome, an autosomal recessive disorder comprising goiter and deafness. Based upon recent work in animals, we hypothesize that asthma and hypertension are less prevalent among humans with SLC26A4 mutations. We tested this hypothesis in 210 subjects. The results are consistent with our hypothesis but do not reach significance due to inadequate study size and statistical power. Our hypothesis might represent an example of balancing natural selection with implications for therapeutic strategies to manipulate SLC26A4 expression or function.