Just in my own circle of friends and acquaintances, I know a large number of families that this generation or the next will be the end of line for their last name, and in some cases for their entire genetic line. Many others are seeing their families condense in such a way that once-blossoming family trees are now dwindling into twigs.
This is a world-wide phenomenon. For all of the Malthusian concerns about world over-population, we are now finding entire nations in crisis as their workforces are starting to be overshadowed by the retirement population. For many countries, the only population growth is coming from immigration (which, ironically, many of their political parties rail against). In some areas, families are going to extraordinary lengths to continue their family lines, including the kidnapping of brides. In higher levels of social status, wealth is being concentrated more and more into the hands of fewer and fewer people.
I believe that there are long-lasting repercussions of this growing trend of dwindling families, some consequences that we are just beginning to feel. It's a hard balance to make: population control and the consequences of that control. I don't know what the best course should be. Hopefully, minds wiser than mine are working on the issue.