Answer:
I can generate fear and some say I come out of your ears. I am as quiet as a mouse but not welcomed in the house.
In my life I must bare, my bloodline I must share. What am I?
When young, I am sweet in the sun. When middle-aged, I make you gay. When old, I am valued more than ever. What am I?
I may be made of metal bone or wood and have many teeth. My bite hurts no one and the ladies love me.
I am the thing that is used to make your weight. What am I?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.