The incidence of autoimmune disease is much higher in women than in men, but women s immune systems are more resistant to infection. When it comes to cancer, a number of gender differences have been observed but not fully explained. Lung cancer, despite popular assumptions to the contrary, is the number one cause of cancer deaths among women, who for some reason seem to be more susceptible to carcinogens in cigarettes. Men and women are equally likely to get colon cancer that is, taking no preventive measures, their risk is the same. However, a high fiber diet appears to be more protective in men than women.
More women get melanoma than men but women tend to survive much longer.
Bladder cancer is more frequent in men, though no one is sure why this is so. The way in which men and women metabolize certain carcinogens may hold a clue. In fact, gender differences in metabolism have been documented for food, alcohol, and environmental toxins. Gender-based differences in mental health, including mental acuity, have also been observed. According to one study, men show a measurable decline in attention, as well verbal and spatial memory, by the young age of 45.