Answer:
A gentleman whose offspring have successfully produced offspring of their own.
What can you keep after giving it to someone?
The thinkers usually hold this body part
If you have me, you want to tell me. If you tell me, you don't have me.
It can be done to buttons and shopping carts. What is it?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?