It goes without saying that a person’s sex should have no bearing on whether one is arrested for DWI. The law is clear: a blood alcohol concentration (BAC) of .08 is considered legal intoxication, and anyone – male or female – who is arrested with that amount of alcohol in their blood is in for a penalty.

What isn’t fair or equal is the number of drinks it takes to arrive at impairment. Generally, women get drunk on less alcohol than men. Which means they need to be extra vigilant when out on the town, because it takes much less drinking to bring about a DWI charge.

It’s not just a matter of size, either. It’s quite likely that a 140 lb. woman will handle alcohol less efficiently than a 140 lb. man, for a variety of reasons.

• One reason is dehydrogenase, an enzyme that helps process alcohol right away in the stomach. Women have less of it, which means that more booze makes beyond the stomach into the small intestine.
• Body fat levels are different in men and women: more fat (comparatively) means less blood, so that the alcohol takes up a greater percentage of it.
• Another factor is good old H20: men have more of it than women do as a percentage of body weight, and water dilutes alcohol. Life just isn’t fair.

So what does this difference in alcohol tolerance mean at the bar, or the party?

Let’s take a man and a woman who, for the sake of comparison, are each 140 pounds. Here’s what happens in their bloodstream when they drink the same amount in a one hour period:

Information source: http://www.drinkinganddriving.org/

As you can see, after the first drink the woman’s BAC will climb higher than the man’s. At two drinks she’s at .07, just short of legal intoxication. The man will have a BAC of .05. Both these levels are too impaired to drive, but the higher level also results in a more compromised judgment – and bad decisions.

You can’t change the effect that alcohol has on your body, but you can be more aware of your drinking. If you’re a woman, don’t feel the need to keep up with the guy you’re with – in terms of physiology, you’ll actually be out-drinking him. Most likely that wasn’t your idea. The safe road is to drink moderately and be aware that it takes time for alcohol to metabolize. You might think you’re okay to have another, but the first one hasn’t taken its full effect yet.

A full BAC chart of men vs. women is here.