"Adult" ads on YGroups that may include children: How can we block ads of this type?

[Garummm]

Our Yahoo Group is private because we anticipate that we will have youth joining us in the future, and because a Yahoo Group is so much more secure than Facebook or other options.

We also recognize that advertising is a necessary feature. Is there any way to de-select "adult" ads? We've been getting more of them lately: "dating" services with semi-nude females, and such like.
Our YGroup is NOT categorized as "adult".

This is embarrassing, after we explain that we use Yahoo because is is a safer option than Facebook for children and youth.

I remember (not sure if it was in Yahoo) that I could select specific categories of ads that I wanted to receive (makes the advertisements more effective, too). There was a certain minimum number of ad categories that I had to select -- with enough margin to allow me to not choose "adult" ads and the like.

This seems to me to be an optimum system: the provider still generates ad revenue, the advertiser gets a more interested audience, and the user can opt out of certain categories.

[Anmol]

Click change your email preferences
on the last line of the invitation and
follow the prompts or:
Click the My Email Preferences link
on the My Groups page.
Under Options, click on the Edit link
for each email address you want to
prevent from being invited/added to
a group.
Under Group Invitations, make sure
the box is not checked next to Allow
group moderators to directly add me
to their groups or Allow group
moderators to invite me to their
groups.
Click Save Changes when you’re
done. ... then it may solve your problem