In 2001, Voskuhl published an article outlining discrepancies in EAE between male and female mice; she noted that females were more susceptible to EAE, mirroring the sex-based difference in MS in humans. It was found that the neuroprotective effects of testosterone contributed most to this discrepancy in mice. However, this sex difference is reduced during late pregnancy in females, when estriol levels are significantly higher than other periods of life.