Multiple sclerosis (MS) is a complex disease characterised by a multifactorial aetiology. Being a woman is the strongest risk factor for MS, by virtue of the sex alone. The existence of a gender bias is well known, since MS occurs more frequently in women than in men.1 2 Moreover, this predilection has increased almost worldwide, over the last few decades, and is the highest in Western countries situated in northern latitudes. Apart from the prominent role of sex hormones, recent modifications in women’s lifestyle have been postulated to cause the increased prevalence of MS in women.1 2. To read the full article, log in using your NHS OpenAthens details.