Some family history - in perspective

This post came about because somebody on Lampwork Etc. posted something about knowing all of his great grandparents. I never knew any of mine.

People sometimes wonder about my age and a bunch more things. I am currently still 55. My parents are both still alive and in their 80s. My youngest grandparent would be 110 now and my oldest would be 139. Those are my grandparents. You can bet that I have never met any great-grandparents (the genes to live long are on the side that had children late).

My parents have a few grandsons (the youngest are about 3 now, they're twins) but only one granddaughter, our daughter, who currently works at icannwiki.com after graduating college last year.

My parents at some point realized that they have children belonging to two different generations. They have grandchildren almost belonging to 3.

My husband is the youngest of his siblings and has a nephew whose oldest is almost the age of our daughter.
I kinda doubt my husband's parents ever had the chance to realize that they had children of different generations. He was the only one who didn't get married until "later in life" - he was 36 when we got married. And they had their first grandkid when my husband was 9.

My youngest nephews could be my oldest nephew's grandchildren by age.
This happened in only two generations, and my husband's parents were only about 10 years older than mine.

Sometimes this strikes me as odd.