If you have more than one child, you may have already figured out sharing is not innate and teaching how to share -- isn't easy.
Clinical psychologist Dr. Kerry Murray-Pertchik is an expert on children's behaviors, she says sibling rivalry is normal, her advice to parents, no matter what age your child is, keep your expectations in check.
"Sometimes parents have unrealistic expectations that their children are going to be best of friends and there's not going to be any fighting back-and-forth, that's not reasonable," said Murray-Pertchik.
Toddlers are notoriously possessive, tips on increasing the peace between them:
"Focusing on the behavior itself and trying to reinforce when you do see sharing behaviors can be very effective but it may not come naturally," said Murray-Pertchik.
The more children you have, the more sibling rivalry you will have, especially when there is a new baby.
"Planning alone time with each child is very important. If there is a new baby and you have an older child be sure to do something with that child that is unique that the baby cannot participate in," said Murray-Pertchik.
As children get into the teen years they want more independence from both mom and siblings. There will be times when the fighting might escalate; the experts say this is the time to let them figure it out on their own.
"Anytime the kids are fighting we ask the parents to step out. Often times we step in too quickly and they never learn how to manage relationships effectively," said Murray-Pertchik.
Effectively is the key word. Parents are encouraged to step in if things get out of hand.