Non-tuberculous mycobacteria (NTM) are environmental microbes that cause a variety of diseases both in immunocompromised and immunocompetent patients. Epidemiologic data indicate that there has been a global rise in the incidence of NTM infections. It has also been noted that NTM infections have a predilection to occur in postmenopausal women. In a recent study, it was demonstrated that in patients with non-CF bronchiectasis the probability of NTM isolation was significantly higher in elderly female patients and in those with a low body mass index. However, the mechanisms of causality of these gender differences and morpho-phenotypes remain enigmatic. The present study reviews the data and plausible mechanisms which might provide clues to this gender susceptibility and morpho-phenotypes of patients with bronchiectasis and NTM.