The Surgeon General has a lot of great infographics on the risk of cancer with alcohol consumption.

As it notes, we have causal evidence that alcohol causes at least 7 types of cancer. It is the third largest preventable cause of cancer behind tobacco and obesity.

Alcohol contributes to 1 in 6 breast cancers in women.

The risk increases with higher consumption. But for breast, mouth, and throat cancers the risk is elevated even with 1 or fewer drinks per day.

I'm a big believer in informed consent with these things.