The window for great-grandmothers is closing

Because the age of great-grandparents is ending, and it didn't last very long either. It's slightly paradoxical - in the past, I've thought about how since life expectancy is increasing, there probably will be more great-grandmothers. Until just one or two generations ago people were having multiple kids, and at very young ages. Even more interesting is that this "Age of great-grandmothers" as I like to call it not only is ending, but it hasn't been here for long either. One can extrapolate it was even lower in the 1900s, and before then too. People had children even earlier, but it was hard to get old enough to have grandkids even in that case. Some people believe we can make significant jumps in longevity over the next century, but provided that doesn't happen, we'll likely see fewer and fewer great-grandmothers around.