Grandchildren make one an ancestor. Once you have raised children to the state where they can begin themselves to raise children, you are a "reproductively successful organism" in evolutionary terms and once I became that, the feeling of ancestorship came over me.
Grandparent-ancestors have the responsibility for conveying the past of the family to their descendants, more so than parents who are busy with raising the children, and besides, grandparents are closer to the past than their children are. My grandchildren were in their early school years when I retired from the world of work and took up the ancestor mantle in all seriousness. Retirement provided - at least theoretically - the time to undertake this responsibility, and to develop a relationship with a computer. The impetus of being a grandparent and the facts of being retired and at least marginally computer-literate, coincided, and I was off and running.
An important ancestor task seemed to me to be to make their ancestors accessible to my descendants. Many of my forebears had had the foresight to make records of their lives, but these records were usually not in an accessible form. Fifty years' worth of five year diaries, five minuscule lines per day in an elegant but cramped hand with many abbreviations, could not be called accessible. Those diaries had to be transcribed and footnoted. The scattered notebooks and memorabilia of another ancestor had to be assembled, transcribed and again footnoted. The writings of my parents too, although more legible, were scattered and needed to be pulled together to form coherent narratives. The letters written to the place of my birth where my grandfather and father homesteaded needed to be assembled, transcribed and footnoted. And those are a few of the score of family history volumes that cried out to be produced, made accessible and shared with the immediate family, and to a limited extent, to the extended family.
And then there are family trees. How very close to impossible they would be without genealogy software! From my early hesitant efforts to discover how many first cousins I had, my family has grown. Almost every day, in response to my known interest and my widespread requests, family information comes to me to be entered into the family data base, with printouts made for all who want them. I like to send the grandparents of my generation printouts of the family trees of any new grandchildren they tell me about! Often these produce information on the parent of the grandchild who married into the family line, and my family of connections grows along with my family of kinship.
My mother always said, "My family can never be too large," as she welcomed new members. My family too can never be too large.