It is a fear I have as well @"Patti J" but I also recognise that there is no more I can do about it than what I am doing. My Dad died when I was 13, my only sister died 3 years before my eldest child was born, my Mum died almost exactly 1 year after my sister. I am the only one who carries the memories of my immediate family and I have tried to incorporate who we were into my family now. I talk about them and try to make them as real as I can. It upsets me at times that my Mum never had the chance to dote on my kids (as she would have) and that my sister never got to have some substitute daughters which she would have loved (she had boys). And I sometimes carry a little resentment that my husband's family's ways will have more meaning to my kids than my family's ways, not through any fault of theirs. As a later-life child, I never knew my grandparents so, really, given that I was also late to parenthood, I can only be grateful that my kid's have known one set.
My kids are teenagers so I don't know if and when they will have children. I only hope that it is when they are ready to and that I will be there and healthy enough to be able to enjoy that time and to give them the help and support that I wished I had.