my son is nearly 4yrs old, he used to call me dad but when i met my wife nearly 2yrs ago he started calling me by my name. i put this down to him hearing everyone else call me by my name, but when i approach him to ask why he wont he changes the subject or if i ask him who i am he says a silly answer. he knows im his dad but he just wont say it and its starting to upset me is there anything i can do