Biologic sex and sex steroids are important factors in clinical and experimental 
stroke and traumatic brain injury (TBI). Laboratory data strongly show that 
progesterone treatment after TBI reduces edema, improves outcomes, and restores 
blood-brain barrier function. Clinical studies to date agree with these data, 
and there are ongoing human trials for progesterone treatment after TBI. 
Estrogen has accumulated an impressive reputation as a neuroprotectant when 
evaluated at physiologically relevant doses in laboratory studies of stroke, but 
translation to patients remains to be shown. The role of androgens in male 
stroke or TBI is understudied and important to pursue given the epidemiology of 
stroke and trauma in men. To date, male sex steroids remain largely evaluated at 
the bench rather than the bedside. This review evaluates key evidence and 
highlights the importance of the platform on which brain injury occurs (i.e., 
genetic sex and hormonal modulators).