In a recently published retrospective study, researchers found men are more likely than women to acquire community associated bloodstream infections, healthcare associated bloodstream infections and surgical site infections. In a review of over 80,000 adult patients, women had higher rates of urinary tract infections, but still had a lower overall rate of blood stream infections. The reasons for these gender differences are unclear; one possible theory may be gender differences in skin. Hair and shaving may also have an effect, as the lack of data demonstrating gender differences in young children support this idea.