Sex Differences to Become Fundamental Element of Alcohol Research at NIAAA: Why the different limits for women and men? And what do we really know about sex differences when it comes to alcohol consumption and alcohol effects? “These are important questions, particularly in light of recent NIH-wide efforts to address sex differences in preclinical research,” notes NIAAA Director George F. Koob, Ph.D. “Some of the basics are well-established, but animal models of alcohol addiction reveal significant differences between males and females, and we have little data thus far to help us understand those differences.”