Hi, I always thought Casino / Gambling related content was a big no-no for AdSense. I got that weird idea by reading their policy on content, also known as AdSense TOS.. Well it seems I was wrong.. On an official (adsense help) page I've found out that in fact MANY things related to Casino / Gambling are allowed and only a couple are not. Like having an actual gambling site and putting adsense on it, or linking to such a site directly, without being a referral.. Did you know about that or wasn't I the last one to know about it?
This is only happen since last year, Adwords start accept gambling ads. However, they never change the Adsense policy The gambling site still not very clear, seems only website from certain country is allowed ( those gambling legal country), not world wide
Gambling / betting is a category since some months in Google Adsense so yes it is allowed if your content is for +18 and your +18 yourself.
default you won't see ads about gamble in adsense unless you "allow" it in dashboard. if your gamble site is legal in your location, then you can put adsense on. but be safe, you can first email google and inform about this like one of my friend did. all work out ok