Interestingly, and in contrast to the requirement of ERα expression in T lymphocytes for the ameliorating effects of pharmacological E2 treatment on experimental autoimmune encephalomyelitis (Lelu et al. 2011), the skeletal response to estrogen treatment in mice lacking ERα expression in T lymphocytes did not differ from the response in control mice. The gene discussed is ESR1; the disease is experimental autoimmune encephalomyelitis.