This is disheartening to hear. You should not have to ask, like ever. My mother would KILL to have grandchildren and would absolutely love to repeat what she calls the best time of her life. She nags me for not having kids and I feel bad because she sees other grandparents and is saddened she is missing out.
I recently overheard a conversation between two older women who were both new grandparents and they conversation was about the pure joy of getting to raise kids again - BUT - you get to go home at night. They loved it!
If you have the right parents then you should never have these reservations. Otherwise it sounds like you have parents who had kids "because that's what you're supposed to do." So they never enjoyed it and dont want to repeat it. My condolences.