"Males generally have leaner muscles and need more oxygen for muscle growth and maintenance—and larger noses mean more oxygen can be breathed. A new study found that the difference in nose size between males and females of European descent starts showing in early puberty, when 95% of body weight gain in males comes from fat-free mass, compared to 85% in females."


http://now.uiowa.edu/2013/11/big-male-nose