I have read and heard that over all to purchase, posess, and consume by onesself is 21. When a minor is supervised by a parent or guardian who is 21 or older that minor may comsume alcohol as long as the minor stays with the parent.
In Wisconsin you have to be 18, even if you have parents consent you still can't get it cause it is child endangerment... The only way you can get it is if you know a tattoo artist and they can come...
Wisconsin has set the age of consent as 18 years old. As long as both parties are 18 or over, there is no criminal issue. If either or both are under the age, charges at some level could be brought.