It’s a phrase dreaded by parents everywhere – “But all of my friends are doing it!” And while the old standby – “If all of your friends jumped off a bridge, would you?” – can be an effective reply, the original plea is still a jolting reminder of the powerful influences that your children’s friendships carry.

This is usually not a problem when the buddies in question are mellow, respectful do-gooders whom you adore. If only that was always the case.
“Unfortunately, the kids who receive attention from adults and attract their peers are often the ones who don’t follow the rules,” says Nina Senatore, a professor of education at Simmons College in Boston.
What do you do when your child chooses a friend whose actions and behavior clashes with your family’s rules and values? Focus on the behavior, not the friendship, child development experts say. And tailor your approach to your child’s age.
In this segment we focus on:
The early years
Kindergarten marks many firsts for children, often including their first meaningful friendship. While these relationships are usually innocent, undesirable behavior can result.
“Research has shown that children as young as 4 years old can be influenced by a friend to behave in a challenging way and to use bad language,” says Elizabeth Hartley-Brewer, author of Making Friends: A Guide to Understanding and Nurturing Your Child’s Friendships.
Kindergarteners are often attracted to more aggressive and hyper peers because they seem exciting. And while this “exciting” friendship might be unappealing to you as the parent and playdate supervisor, don’t immediately discourage the relationship. Instead, provide the best circumstances for it. Hartley-Brewer recommends alternating playdates between a physically energetic option and a clearly focused activity so that children become too absorbed and busy to make mischief.
“The hyper behavior won’t last long after the dynamo has gone home,” she says. “Your child will soon revert to being calm if you set the right mood and remain calm yourself. Children learn so much about people from their friendships that it’s better to have a slightly wild friend than none at all.”
(Source: parenthood.com