Personally, I only blackout very shortly before becoming violently ill (usually). Anyway, there's a few reasons that women are more impacted by alcohol than are men. 1. men on average have more of the enzyme which breaks down alcohol before it enters the bloodstream (ADH) 2. Women have, on average a higher body fat percentage, which increases the effects of alcohol 3. Women are, at the same time, smaller on average than men, while drinks are a standard size. There's an okay summary of this information here:
http://www.attcnetwork.org/explore/priorityareas/science/tools/asmeDetails.asp?ID=55 if you are interested. Obviously, different people's individual physiological makeup plays an important role. As the author mentions, if you have a tendency to be able to "hold your liqour" you're more likely to experience blackouts. You're also more likely to develop problems with alcohol (I don't have a source for that last bit right now, but if I find it again, I'll post).