The perfect son

A: I have the perfect son. 
B: Does he smoke? 
A: No, he doesn't. 
B: Does he drink whiskey? 
A: No, he doesn't. 
B: Does he ever come home late? 
A: No, he doesn't. 
B: I guess you really do have the perfect son. How old is he? 
A: He will be six months old next Wednesday.