Multiple sclerosis (MS) varies considerably in the way that it affects females and males. The prevalence of the disease is much greater in women and tends to follow a different clinical course than it follows in the affected male population. It is also well known that MS symptoms often are much less of a problem during pregnancy. This chapter discusses possible explanations for gender differences based on sex hormones as well as the effects of these hormones on cytokines and other factors that may influence the course of MS. Knowledge of these effects may hold some promise in other types of treatment for MS. Since MS is much more prevalent in women of child-bearing age, there are also implications for the use of disease-modifying agents as well as drugs and treatments that may be useful for treatment of MS. MS often causes symptoms of sexual dysfunction, but there may be effective treatment for many of these treatments.