For women, binge drinking is defined as having drinks in one sitting.

The answer is 4 drinks
For men on the other hands the number increase from 4 to 5 drinks in one setting. This number is influenced by Men's ability to metabolize alcohol faster compared to women. Which make men tend to have a higher thresold for the amount of alcohol needed before their behavior started to be affected by it.

Women tend to metabolize alcohol at a different rate than men. Women also have less of a concentration of water in their bodies than men. This means that men are able to dilute alcohol more efficiently. For women, the binge drinking number is four.