My 4yr old son has started pulling down pants and peeing on carpet when no one is watching. ps. i'm due to deliver his baby brother in 5 weeks i don't know if this could have anything to do with it.

May be related: It is certainly proper to confront him over the issue & discipline him any way you would normally.Some early born kids feel isolated when their parents spend time discussing the newborn to come.Involving the "Big Brother" aspect to include him in planning can help. Asking him to pick out old baby toys big boys don't play with any more helps. A consultation with a child behavior specialist may help